Troubleshooting
Guide
diesel - gasoline - LPG
P/N 0172021
June 1999
P.O. Box 1160 ƒ St. Joseph, MO 64502-1160
1-800-255-0317 ƒ Fax: 816-360-9379
www.snorkelusa.com
GENERAL INFORMATION
This manual contains procedures for locating and correcting the majority of problems which may
develop on the “Snorkelift” TB 37 Aerial Platform.
Since the majority of malfunctions experienced on equipment in the aerial platform Industry are
associated with the hydraulic and electrical systems, great effort has been made to develop a guide
which insures that procedures regarding these areas are given the fullest possible attention and detail.
As a result of these efforts, the aerial platform has been divided into twelve distinct groups with each
group covered by an individual section. The Sections are as follows:
1.) Engine Diagnostics
2.) Hydraulic Pump Diagnostics
3.) Steering System Diagnostics
4.) Drive System Diagnostics
5.) Emergency Power System Diagnostics
6.) Swing System Diagnostics
7.) Platform Rotation System Diagnostics
8.) Platform Leveling System Diagnostics
9.) Boom Elevation System Diagnostics
10.) Telescope System Diagnostics
11.) Fuel System Diagnostics
12.) Accessories Diagnostics
NOTES, CAUTIONS AND DANGERS
The terms NOTE, CAUTION, and DANGER appear throughout this manual and have specific meanings.
A NOTE provides additional or special information to make a step or procedure easier or
clearer. Disregarding a NOTE might cause inconvenience, but would not cause equipment damage or
personal injury.
A
is provided in a procedure wherever minor personal injury or equipment
damage could result. Disregarding a CAUTION could cause damage to the machine; however serious
personal injury is unlikely.
is the most serious and emphasizes areas where personnel injury and even
death could result from negligence. Permanent mechanical damage is also highly probable. DANGER
signs are to be taken seriously. In some cases, serious injury or death has resulted from disregarding
a DANGER.
NOTE: Engine maintenance and troubleshooting information not contained in this manual may be
found in the engine maintenance manual originally provided with the machine, or from the Engine
Manufacture/Dealer Network.
It should be recognized that every person who performs testing and diagnostic procedures and every
person supervising any of these functions must be properly trained and qualified. If a problem should
occur which is not covered by this manual or which cannot be corrected using the listed corrective
actions, technically qualified guidance from the Service Department of Snorkel International Inc.,
should be obtained prior to proceeding further. Tel: (816) 364-0317
NOTE: Diagnostic procedures basically consist of a logical process of elimination. For this reason,
it is very important that the steps be performed in the order in which they are presented. Always begin
by localizing the problem and defining the symptoms as accurately as possible. When the problem has
been localized, make sure to completely read and comprehend the appropriate flow chart. Do not
attempt to make shortcuts.
1
MANUAL DESIGN
Each symptom described is followed by a list of inspections to be performed. Each inspection is in the
form of a flowchart. A set of detailed checks are then performed at the component and/or related areas
which confirm or decline the outcome. If the inspection is declined the flowchart will refer to the next
step to be performed until the problem is confirmed. The diagnosis then enables a determination.
Example: Problem Solving Procedure
Step 1
Problem
Inspect
Step 2
Go to Page
OK
Inspect
Go to Page
Example: Flowchart Procedure
Inspect
If
Troubleshoot
(Identify Problem)
Yes
Go to step
no
Replace or
perform repair
EQUIPMENT NEEDED:
Multimeter: A meter designed to read voltage, amperage and resistance.
Pressure Test Gauge: A pressure gauge rated for 0 - 1000 psi.
A pressure gauge rated for 0 - 5000 psi.
Tachometer: A meter designed to measure engine RPM on gas and/or diesel.
(Photo Tachometer is recommended)
Flowmeter: A meter designed to measure fluid flow.
Stopwatch: A tool designed to measure time.
2
SYMPTOM
PAGE NUMBER
Section One - Engine Diagnostics
9
Engine starter fails to operate (No Electrical)
Starter disengages before engine starts
10
Engine cranks over but will not start
10
Engine starts then shuts down after 30 seconds
11
Engine will not accelerate
11
Engine over accelerates
12
Engine will not start from platform control
12
Engine starts while cranking, then dies when key switch is released
13
Section Two - Hydraulic Diagnostics
Hydraulic system functions on emergency power only
39
Hydraulic pump stays on stroke
39
Hydraulic oil overheats during operation
39
Hydraulic functions are sluggish
40
Hydraulic pump will not build pressure
40
Hydraulic pump will not build enough pressure
40
Flow from hydraulic pump is too low
40
Flow from hydraulic pump is too high (kills engine)
41
Section Three - Steering System Diagnostics
53
Machine will not steer
3
SYMPTOM
PAGE NUMBER
Section Four - Drive System Diagnostics
Drive system is not operational with controller in either direction
61
No forward drive (Reverse OK)
62
No reverse drive (Forward Ok)
62
Drive high range not operating
63
Machine drives at full speed with platform raised and/or extended
63
Brakes will not release
63
Only one wheel turns (2 wheel drive)
64
One wheel turns faster than other (2 wheel drive)
64
Section Five - Emergency Power System Diagnostics
Emergency pump motor non-operational
85
No functions when on emergency power
85
Section Six - Swing System Diagnostics
Swings only in one direction
93
No response from swing when platform controls are activated (Ground Controls Ok)
93
No response from swing when ground controls are activated
93
Swings erratically in either direction
94
Swings faster one way than other
94
Swing brake will not hold
94
Swings too slow
95
Section Seven - Platform Rotation System Diagnostics
Platform rotate does not operate
109
Platform rotates itself
109
4
SYMPTOM
PAGE NUMBER
Section Eight - Platform Leveling System Diagnostics
Platform will not maintain level as boom raises or lowers
115
Platform will not maintain level with machine off
115
Platform level will not work from ground control
115
Platform level will not work from platform control (Ground Control Ok)
116
Platform level up function is inoperative
116
Platform level down function is inoperative
116
Section Nine - Boom Elevation System Diagnostics
Boom raises but will not stay elevated
129
Boom will not raise from platform control (Ground Control Ok)
129
Boom will not raise from ground control
129
Section Ten - Telescope System Diagnostics
Boom will not retract from ground control
137
Boom will not retract from platform control (Ground Control Ok)
137
Boom will not extend from ground control
137
Boom will not extend from platform control (Ground Control Ok)
138
Boom drifts in
138
Section Eleven - Fuel System Diagnostics
Engine will not start on gasoline, but will start on L.P.
151
Engine will not start on L.P., but will start on gasoline
151
5
SYMPTOM
PAGE NUMBER
Section Twelve - Accessories Diagnostics
AC Generator will not function
159
AC Generator has low voltage
159
Machine will not steer
159
6
SECTION ONE:
ENGINE DIAGNOSTICS
SECTION ONE
ENGINE DIAGNOSTICS
Chart 1
Engine starter
fails to operate
(No Electrical)
Step 1
Inspect
Battery and Cable Connections
Step 2
OK
Inspect
Power Cables and
Battery Disconnect Switch
Step 3
Go to Page
18
OK
Inspect
Starter Solenoid
Troubleshooting Guide
Go to Page
18
OK
Inspect
Engine Starter Relay
Step 11
Go to Page
17
OK
Inspect
Engine Anti-Restart Relay
Step 10
Go to Page
17
OK
Inspect
Ground/Platform
Selector Switch
Step 9
Go to Page
16
OK
Inspect
Ignition/Emergency
Power Switch
Step 8
Go to Page
16
OK
Inspect
Ground Master (Key) Switch
Step 7
Go to Page
15
OK
Inspect
Emergency Stop Switch
Step 6
Go to Page
15
OK
Inspect
Ground Control
Circuit Breaker (25 Amp)
Step 5
Go to Page
14
OK
Inspect
Ammeter
Step 4
Go to Page
14
9
Go to Page
19
TB 37
SECTION ONE
ENGINE DIAGNOSTICS
Chart 2
Step 1
Starter
disengages before
engine starts
Inspect
Engine Anti-Restart Relay
Step 2
Go to Page
20
OK
Inspect
Starter Solenoid
Go to Page
20
Inspect
Ground Master (Key) Switch
Go to Page
21
Chart 3
Step 1
Engine cranks
over but
will not start
Step 2
OK
Inspect
Ground/Platform Selector Switch
Step 3
OK
Inspect
Ignition/Emergency Power Switch
Step 4
OK
Go to Page
22
OK
Inspect
Run Relay
Step 5
Go to Page
21
Go to Page
22
OK
Inspect
Magnetic Switch
(Ford only)
Go to Page
23
Inspect
Magnetic Switch
(Deutz only)
Go to Page
23
Step 6
Step 7
OK
Inspect
Run Solenoid
(Deutz only)
Troubleshooting Guide
10
Go to Page
24
TB 37
SECTION ONE
ENGINE DIAGNOSTICS
Chart 4
Step 1
Engine starts
then shuts down
after 30 seconds
Inspect
Engine Temperature Gauge
Step 2
Go to Page
25
OK
Inspect
Engine Oil Pressure Switch
Go to Page
25
Chart 5
Step 1
Engine will not
accelerate
Inspect
Throttle Circuit Breaker (15 Amp)
Step 2
OK
Inspect
Medium Throttle Relay
(Ford only)
Step 3
Step 4
Go to Page
27
OK
Inspect
Throttle Governor or Controller
(Ford only)
Step 5
Go to Page
26
OK
Inspect
High Throttle Relay
(Ford only)
OK
Go to Page
26
Go to Page
27
OK
Inspect
Actuator
(Ford only)
Go to Page
28
Inspect
Throttle Relay
(Deutz only)
Go to Page
28
Step 6
Step 7
OK
Inspect
Throttle Solenoid
(Deutz only)
Troubleshooting Guide
11
Go to Page
29
TB 37
SECTION ONE
ENGINE DIAGNOSTICS
Chart 6
Step 1
Engine over
accelerates
Inspect
Governor
(Ford only)
Step 2
Go to Page
30
OK
Inspect
Actuator
(Ford only)
Go to Page
30
Inspect
Ground/Platform Selector Switch
Go to Page
31
Chart 7
Engine will not
start from
platform control
Step 1
Step 2
OK
Inspect
Platform Control
Circuit Breaker (20 Amp)
Step 3
OK
Inspect
Emergency Stop Switch
Step 4
Go to Page
32
OK
Inspect
Ignition/Emergency Power Switch
Troubleshooting Guide
Go to Page
32
OK
Inspect
Platform Start Switch
Step 6
Go to Page
32
OK
Inspect
Foot Switch
Step 5
Go to Page
31
12
Go to Page
33
TB 37
SECTION ONE
ENGINE DIAGNOSTICS
Chart 8
Engine starts while
cranking, then dies
when key switch is
released
Step 1
Inspect
Run Solenoid
Step 2
OK
Inspect
Murphy Switch
Step 2
Go to Page
34
OK
Inspect
Vacuum Switch
(Ford only)
Troubleshooting Guide
Go to Page
34
13
Go to Page
35
TB 37
SECTION ONE
ENGINE DIAGNOSTICS
Engine starter fails to
operate (No Electrical)
Batteries omit hydrogen
and oxygen elements that
can combine explosively.
Do not smoke or permit
open flames or sparks
when checking batteries
Recharge or
replace
battery(s)
If low or no voltage
Inspect
Batteries
Using a meter
set to read
voltage, check
each battery for
12 volts while
under load
Clean all
connections
If 12V
Check battery
connections
If
corroded
If loose
Tighten all
connections
Step 1
Step 2
Using a meter set to
read voltage, measure
voltage entering
Battery Disconnect Switch
Should read 12-12.7 volts
Inspect
Power Cables and
Battery Disconnect
Switch
If
If 12-12.7V
Battery Disconnect
Switch in Off
Position
Then
Reset Battery
Disconnect Switch
to On Position
If
12-12.7V
Using a meter set to
read voltage, turn
Battery Disconnect Switch
to On position, measure
voltage coming out of
Battery Disconnect Switch
Should read 12-12.7 volts
If low or no reading
Go to step 3
Troubleshooting Guide
14
Repair or replace
Battery Disconnect Switch
and/or
Battery Disconnect Switch
wiring
TB 37
SECTION ONE
ENGINE DIAGNOSTICS
Inspect
Ammeter
If
12-12.7V
Using a meter set to read
voltage, measure voltage
between
1.Battery Disconnect
Switch and Ammeter (+)
on wire # 57
2.Ammeter (-) and Circuit
Breaker on wire #1A
Should read 12-12.7 volts
If low or no reading
Repair or replace
Circuit Breaker
and/or
Circuit Breaker wiring
Go to step 4
Step 3
Step 4
Inspect
Ground Control
Circuit Breaker
(25 Amp)
Using a meter set to read
voltage, turn Battery
Disconnect Switch to
On position,
measure voltage entering
Emergency Stop Switch
Should read 10-12 volts
If
Circuit breaker is
open
If low or no reading
Then
Reset Circuit
breaker
If
10-12V
Check for voltage between
Circuit Breaker and
Emergency Stop Switch
on wire #1A
Should read 12 volts
If low or no reading
Go to step 5
Troubleshooting Guide
15
Repair or replace
Circuit Breaker
and/or
Circuit Breaker wiring
TB 37
SECTION ONE
ENGINE DIAGNOSTICS
Inspect
Emergency Stop
Switch
Using a meter
set to read voltage, pull
Emergency Stop Switch
out and measure
voltage between
Emergency Stop Switch
and Battery side of
Ground Master
(Key) Switch.
Should read 10-12 volts
If
Emergency Stop
Switch is off
(pushed in)
Then
Pull Emergency
Stop Switch (out)
to the On position
If
10-12V
If low or no reading
Replace
Emergency Stop Switch
and/or
Emergency Stop Switch
wiring
Go to step 6
Step 5
Step 6
Inspect
Ground Master
(Key) Switch
Go to step 7
If
10-12V
Using a meter set to read
voltage, activate engine
starter and measure
voltage between Battery
post side of Ground
Master Switch and start
side of Ground
Master Switch.
Should read 10-12 volts
If low or no reading
Repair or replace
Ground Master Switch
and/or
Ground Master Switch
wiring
Troubleshooting Guide
16
TB 37
SECTION ONE
ENGINE DIAGNOSTICS
Inspect
Ignition/Emergency
Power Switch
Go to step 8
If
10-12V
Using a meter set to
read voltage, activate
engine starter and
measure voltage
between
Ground Master Switch and
Ignition/Emergency Power
Switch
Should read 10-12 volts
If low or no reading
Replace
Ignition/Emergency Power
Switch and/or
Ignition/Emergency Power
Switch wiring
Step 7
Step 8
Inspect
Ground/Platform
Selector Switch
Set Selector Switch to
Ground position. Using a
meter set to read voltage,
activate starter and
measure voltage between
Ignition/Emergency Power
Switch and Ground/
Platform Selector Switch
Should read 10-12 volts
If
Ground/Platform
Selector Switch is
in Platform position
Then
Return Ground/
Platform Selector
Switch to Ground
position
Go to step 9
Troubleshooting Guide
17
If low or no reading
If
10-12V
Replace
Ground/Platform Selector
Switch and/or
Ground/Platform Selector
Switch wiring
TB 37
SECTION ONE
ENGINE DIAGNOSTICS
Inspect
Engine AntiRestart Relay
Replace
wiring to
Engine Anti
Restart Relay
If low
or no
reading
Using a meter set to
read voltage, activate
engine starter and
measure voltage
between Ground Control
Switch and Anti-Restart
Relay on wire #5C.
Should read 10-12 volts
If 10-12v
Go to step 10
If
10-12v
Measure voltage at
wire #5B.
Should read 10-12 volts
If low or no reading
Replace
Engine AntiRestart Relay
If still
does
not
engage
Check Adjustable Resistor
between Terminal
164 and 164B, Adjust as
needed for starter to
engage.
Step 9
Step 10
Inspect
Engine Starter
Relay
Check ground
continuity
No continuity
Continuity
Replace
Engine Starter
Relay
Go to step 11
Troubleshooting Guide
18
If
10-12V
Using a meter set to
read voltage, activate
engine starter and measure
voltage from
1. wire #5B to Starter
Relay.
2. wire from Starter
Relay to Ground
Should read 10-12 volts
If low or no reading
Replace
Engine Starter Relay wiring
TB 37
SECTION ONE
ENGINE DIAGNOSTICS
Inspect
Starter Solenoid
Check ground
continuity
No continuity
Continuity
Replace
Starter Solenoid
Return to step 1
If
10-12V
Using a meter set to
read voltage, activate
engine starter and measure
voltage from
1. wire #5A to Starter
Solenoid
2. Starter Solenoid to
Ground
Should read 10-12 volts
If low or no reading
Replace
Starter Solenoid wiring
Step 11
Troubleshooting Guide
19
TB 37
SECTION ONE
ENGINE DIAGNOSTICS
Starter disengages
before engine starts
Inspect
Engine AntiRestart Relay
Continuity
Open field in alternator
Disconnect wire 164B
from Alternator. Check
continuity between post
and alternator case.
No continuity
Repair or replace
Alternator
Adjust resistor for longer
cranking time, until engine
starts and alarm shuts off.
(approx. 30 seconds)
Locate the adjustable
resistor between terminals
#164 and #164B, remove
the plastic covering.
While activating the starter,
slowly slide adjuster until
cranking time is sufficient
for starting engine.
Replace the plastic
covering.
Step 1
Step 2
Inspect
Starter Solenoid
Check ground
continuity
No continuity
Continuity
Replace
Starter Solenoid
Return to step 1
Troubleshooting Guide
20
If
10-12V
Using a meter set to
read voltage, activate
engine starter and measure
voltage from
1. wire #5A to Starter
Solenoid
2. Starter Solenoid to
Ground
Should read 10-12 volts
If low or no reading
Replace
Starter Solenoid wiring
TB 37
SECTION ONE
ENGINE DIAGNOSTICS
Engine cranks over
but will not start
Inspect
Ground Master
(Key) Switch
Go to step 2
If
10-12V
Using a meter set to read
voltage, activate engine
starter and measure
voltage between Battery
post side of Ground Master
Switch and ignition side of
Ground Master Switch.
Should read 10-12 volts
No reading
Repair or replace
Ground Master Switch
and/or
Ground Master Switch
wiring
If reading
is low
Check Battery
Step 1
Step 2
Set Selector Switch to
Ground position. Using a
meter set to read voltage,
activate starter and
measure voltage between
Ignition/Emergency Power
Switch and Ground/
Platform Selector Switch
Should read 10-12 volts
Inspect
Ground/Platform
Selector Switch
If
Ground/Platform
Selector Switch
is in
Platform position
Then
Troubleshooting Guide
If
10-12V
No reading
Return Ground/
Platform Selector
Switch to Ground
position
Replace
Ground/Platform Selector
Switch and/or
Ground/Platform Selector
Switch wiring
Go to step 3
Check Battery
21
TB 37
If
reading
is low
SECTION ONE
ENGINE DIAGNOSTICS
Inspect Ignition/
Emergency Power
Switch
Go to step 4
If
10-12V
Using a meter set to
read voltage,
measure voltage
entering Ignition/
Emergency Power Switch
Should read 10-12 volts
If low or no reading
Replace
Ignition/Emergency
Power Switch and/
or
Ignition/Emergency
Power Switch
wiring
If low
or no
reading
Check voltage on diode
wire between Ignition/
Emergency Power Switch
and Ground/Platform
Switch. Replace diode wire
if faulty. Measure voltage
entering Run Relay
(wire #4A)
Should read 10-12 volts
Step 3
Step 4
Inspect
Run Relay
Go to step 5
(Ford)
Go to step 6
(Deutz)
If
10-12V
Using a meter set to
read voltage,
measure voltage
between Run Relay and
Murphy Switch (B Post)
wire #164
Should read 10-12 volts
If low or no reading
Replace
Ground/Platform Selector
Switch and/or
Ground/Platform Selector
Switch wiring
Troubleshooting Guide
22
TB 37
SECTION ONE
ENGINE DIAGNOSTICS
Inspect
Magnetic Switch
( Ford only)
Replace
Engine Spark
Module
If Ok
Using a meter set to read
voltage, measure voltage
on wire
1. at post NC of
Magnetic Switch
2. on wire 80 between
Magnetic Switch and
Engine Spark Module
Should read 10-12 volts
If low or no reading
Replace
Magnetic Switch and/or
Magnetic Switch wiring
Step 5
Step 6
Inspect
Magnetic Switch
( Deutz only)
Go to step 7
If Ok
Using a meter set to
read voltage,
measure voltage on wire
#8D at post NC of
Magnetic Switch
Should read 10-12 volts
If low or no reading
Replace
Magnetic Switch and/or
Magnetic Switch wiring
Troubleshooting Guide
23
TB 37
SECTION ONE
ENGINE DIAGNOSTICS
Inspect
Run Solenoid
( Deutz only)
Repair Wire
If low
or no
reading
Using a meter set to
read voltage,
measure voltage at wire
#8D to Run Solenoid
Should read 10-12 volts
Note: Check continuity
to ground on white
jumper wire
If Ok
Replace
Run Solenoid
Step 7
Troubleshooting Guide
24
TB 37
SECTION ONE
ENGINE DIAGNOSTICS
Engine starts then shuts
down after 30 seconds
Inspect
Engine
Temperature
Gauge
Repair Wire
If low
or no
reading
Using a meter set to
read ohms,
Check continuity on wire
between Murphy Switch
(Black wire at S post) and
Chassis ground
If resistance is shown
Allow time for Engine to
cool down
Then
Replace
Murphy Engine
Temperature Gauge
Step 1
Step 2
Inspect
Engine Oil
Pressure Switch
If oil level
is adequate
Remove wire #3C from Oil
Pressure Switch.
Restart engine
If
If engine still dies
Engine oil
pressure is due to
inadequate oil level
Using a meter set to read
ohms, check for continuity
from wire #3C to Ground
Should not read continuity
Then
Fill to proper level
with oil
If engine
now ok
If no
continuity
If continuity exists
Repair Wire
Return to step 1
Replace
Engine Oil Pressure Switch
Troubleshooting Guide
25
TB 37
SECTION ONE
ENGINE DIAGNOSTICS
Engine will not
accelerate
Inspect
Throttle Circuit
Breaker (15 Amp)
Using meter set to read
voltage, measure voltage
Ford: entering either
Medium Throttle Relay wire
#55A or High Throttle
Relay wire #55B
Deutz: on wire #55A
between Throttle Relay
and Throttle Solenoid
Should read 10-12 volts
If
Circuit breaker is
open
Then
Reset Circuit
breaker
If low or no reading
Go to step 2
(Ford)
Go to step 6
(Deutz)
If
continuity
does
exists
Check continuity on wire
#55 between Throttle
Circuit Breaker and
Medium Throttle Relay or
High Throttle Relay
If continuity does not exists
Repair or replace
Circuit Breaker and/or
Circuit Breaker wiring
Step 1
Step 2
Inspect
Medium Throttle
Relay
(Ford only)
Go to step 3
If
10-12V
Using a meter set to
read voltage,
measure voltage
on wire #55A to
Throttle Controller
Should read 10-12 volts
If low or no reading
Check continuity on wire
between Medium Throttle
Relay and Throttle
Controller
Then
Repair or replace
wiring from
Medium Throttle Relay
to Throttle Controller
Troubleshooting Guide
26
TB 37
SECTION ONE
ENGINE DIAGNOSTICS
Inspect
High Throttle
Relay
(Ford only)
If
10-12V
Go to step 4
Using meter set to
read voltage,
measure voltage
on wire #55B to
Throttle Controller
Should read 10-12 volts
If low or no reading
Check continuity on wire
between High Throttle
Relay and Throttle
Controller
Then
Repair or replace
wiring from
High Throttle Relay
to Throttle Controller
Step 3
Step 4
Inspect
Electronic
Governor
(Ford only)
If
10-12V
Go to step 5
Using a meter set to
read voltage,
measure voltage
on wire #55A and #55B
going into the
Electronic Governor
Should read 10-12 volts
If low or no reading
Repair or replace
wiring to
Electronic Governor
Troubleshooting Guide
27
TB 37
SECTION ONE
ENGINE DIAGNOSTICS
Inspect
Actuator
Repair or replace
Electronic
Governor
If
10-12V
Using a meter set to
read voltage,
measure voltage,
on wire #A1
and #A2 between the
Electronic Governor
and Solenoid
Should read 10-12 volts
If low or no reading
Repair or replace
Electronic Governor
and/or wiring
Step 5
Step 6
Inspect
Throttle Relay
(Deutz only)
If
10-12V
Go to step 7
Using a meter set to
read voltage,
measure voltage
on wire #55A between
Throttle Circuit Breaker
and Throttle Solenoid
Should read 10-12 volts
If low or no reading
Check continuity on wire
between Throttle
Circuit Breaker
and Throttle Solenoid
If no continuity
Repair or replace
wiring between
Throttle Circuit Breaker
and Throttle Solenoid
Troubleshooting Guide
28
TB 37
SECTION ONE
ENGINE DIAGNOSTICS
Inspect
Throttle Solenoid
(Deutz)
Using meter set to read
voltage, measure voltage
1. on wire #55A going
into Throttle Solenoid
2. on wire #55A between
Throttle Solenoid and
ground
Should read 10-12 volts
If low or no reading
Repair or replace
Throttle Solenoid
and/or
Throttle Solenoid wiring
If problem still exists
Adjust Throttle Solenoid
Step 7
Troubleshooting Guide
29
TB 37
SECTION ONE
ENGINE DIAGNOSTICS
Engine over
accelerates
Inspect
Electronic
Governor
Go to step 2
If
10-12V
Using a meter set to
read voltage,
measure voltage,
on wire #55A and #55B
going into the
Electronic Governor
Should read 10-12 volts
If low or no reading
Repair or replace
Ford: wiring to
Electronic Governor
Step 1
Step 2
Inspect
Actuator
Repair or replace
Electronic
Governor
If
10-12V
Using a meter set to
read voltage,
measure voltage
on wire #A1
and #A2 between the
Electronic Governor
and Actuator
Should read 10-12 volts
If low or no reading
Repair or replace
Electronic Governor
and/or wiring
Troubleshooting Guide
30
TB 37
SECTION ONE
ENGINE DIAGNOSTICS
Engine will not start
from platform control
Inspect
Ground/Platform
Selector Switch
Set Selector Switch to
Platform position. Using a
meter set to read voltage,
activate starter and
measure voltage between
Ignition/Emergency Power
Switch and Ground/
Platform Selector Switch
Should read 10-12 volts
If
Ground/Platform
Selector Switch is
in Ground position
Then
Return Ground/
Platform Selector
Switch to Platform
position
Go to step 2
If low or no reading
If
10-12V
Replace
Ground/Platform Selector
Switch and/or
Ground/Platform Selector
Switch wiring
Step 1
Step 2
Inspect
Platform Control
Circuit Breaker
(20 Amp)
Using a meter set to read
voltage, turn Ground/
Platform Switch to Platform
position, measure voltage
on wire #1 and #2
entering Platform Control
Circuit Breaker
Should read 10-12 volts
If
Circuit Breaker is
open
Then
If 10-12V
Reset
Circuit Breaker
Go to step 3
Replace
Circuit Breaker
Troubleshooting Guide
31
If
10-12V
If low
or no
reading
Check for voltage on
wire #1B to Emergency
Stop Switch
Should read 10-12 volts
Repair or replace
Wire #1 and/or #2
TB 37
If low
or no
reading
SECTION ONE
ENGINE DIAGNOSTICS
Emergency Stop
Switch is off
(pushed in)
Using a meter set to read
voltage, pull Emergency
Stop Switch out and
measure voltage between
Emergency Stop Switch
and Battery side of
Platform Master Switch.
Should read 10-12 volts
Then
If low or no reading
Inspect
Emergency Stop
Switch
If
Pull Emergency
Stop Switch (out)
to the on position
Go to step 4
Step 3
Step 4
If
10-12V
Inspect
Foot Switch and
Wiring
Replace
Emergency Stop Switch
and/or
Emergency Stop Switch
wiring
Make sure Foot Switch is
not activated
If activated
If
not
activated
Go to step 5
If
10-12V
Deactivate Foot Switch
Using a meter set to read
voltage, measure voltage
on wire #10 going into
Foot Switch and
wire #8 coming out
of Foot Switch
Should be 10-12 volts
If low or no voltage
Repair or replace
Foot Switch
and/or wiring
Troubleshooting Guide
32
TB 37
SECTION ONE
ENGINE DIAGNOSTICS
Inspect
Platform Start
Switch
Go to step 6
If
10-12V
Using a meter set to
read voltage, activate
Platform Start Switch and
measure voltage on
wire #5 between
Platform Start Switch and
Platform Emergency Power
Switch
Should read 10-12 volts
If low or no reading
Replace
Platform Start Switch
and/or
Platform Start Switch
wiring
Step 5
Step 6
Inspect
Ignition/Emergency
Power Switch
Return to step 1
If
10-12V
Using a meter set to
read voltage, activate
engine starter and
measure voltage
on wire #5 between
Platform Master Switch
and Ignition/Emergency
Power Switch
Should read 10-12 volts
If low or no reading
Replace
Ignition/Emergency Power
Switch and/or
Ignition/Emergency Power
Switch wiring
Troubleshooting Guide
33
TB 37
SECTION ONE
ENGINE DIAGNOSTICS
Engine starts while
cranking, then dies when
key switch is released
Inspect
Run Relay
Go to step 2
If
10-12V
Using a meter set to
read voltage,
measure voltage
at Murphy Switch wire
#164, B post of
Murphy Switch
Should read 10-12 volts
If low or no reading
Repair or replace
Run Relay
and/or
Run Relay wiring
Step 1
Step 2
Inspect
Murphy Switch
Ford
Go to step 3
If
10-12V
Using a meter set to read
voltage, measure voltage
on wire
Ford: on wire #80 to
Spark Module
Deutz: #8D between Run
Solenoid and Murphy
Switch
Should read 10-12 volts
Note: Check continuity
to ground on white
jumper wire
If low or no reading
Replace
Murphy Switch
Troubleshooting Guide
34
TB 37
SECTION ONE
ENGINE DIAGNOSTICS
Inspect
Vacuum Switch
(Ford only)
Check continuity on wire
between Ignition and
Solenoid when switch is in
normally closed position
If no continuity
Replace
Vacuum Switch
Step 3
Troubleshooting Guide
35
TB 37
SECTION TWO:
HYDRAULIC DIAGNOSTICS
SECTION TWO
HYDRAULICS DIAGNOSTICS
Chart 1
Hydraulic system
functions on
emergency power
only
Step 1
Inspect
Main Hydraulic Pump
Step 2
OK
Inspect
Sense Line Dump Valve
Step 3
Go to Page
42
Go to Page
42
OK
Inspect
Sense Line check Valve
Go to Page
43
Chart 2
Step 1
Hydraulic pump
stays on stroke
Inspect
Pump Compensator
Go to Page
44
Inspect
Functions Valve
Go to Page
44
Chart 3
Hydraulic oil
overheats
during operation
Troubleshooting Guide
Step 1
39
TB 37
SECTION TWO
HYDRAULICS DIAGNOSTICS
Chart 4
Step 1
Hydraulic functions
are sluggish
Inspect
Engine RPM
Step 2
OK
Inspect
Pump Pressure
Step 3
Go to Page
45
OK
Inspect
Accumulator
Step 4
Go to Page
45
Go to Page
46
OK
Inspect
Flow from Pump
Go to Page
46
Inspect
Pump Compensator Valve
Go to Page
47
Chart 5
Step 1
Hydraulic pump will
not build pressure
Step 2
OK
Inspect
Pump Coupling
Go to Page
47
Inspect
Pump Compensator Valve
Go to Page
48
Chart 6
Hydraulic pump
will not build
enough pressure
Step 1
Step 2
OK
Inspect
Senseline Dump Valve
Go to Page
48
Inspect
Flow Adjustment on Main Hydraulic
Pump
Go to Page
49
Chart 7
Flow from
hydraulic pump
is too low
Troubleshooting Guide
Step 1
40
TB 37
SECTION TWO
HYDRAULICS DIAGNOSTICS
Chart 8
Flow from
hydraulic pump
is too high
(kills engine)
Troubleshooting Guide
Step 1
Inspect
Flow Adjustment on
Main Hydraulic Pump
41
Go to Page
49
TB 37
SECTION TWO
HYDRAULICS DIAGNOSTICS
Hydraulic system
functions on emergency
power only
Inspect
Main Hydraulic
Pump
Remove gauge
and
Go to step 2
Replace
Main Hydraulic
Pump and/or Pump
Coupling and/or
Pump
Compensator
If
300 psi
Install 1000 psi pressure
gauge to hydraulic pump
test plug. Set engine for
idle and measure
differential/standby
pressure.
Should read 300 psi
If reading is abnormal
If
malfunctioning
Check
Main Hydraulic Pump,
Pump Coupling and
Pump Compensator
Step 1
Step 2
Inspect
Sense Line Dump
Valve
Check seals on
Sense Line Dump
Valve
If bad
Ok
Repair or replace
Sense Line Dump
Valve
Go to step 3
Troubleshooting Guide
42
If
10-12V
Using a meter set to read
voltage, activate Ground
Control Switch and
measure voltage
1.on wire #28B between
Terminal Strip
in Junction Box and
Sense Line Dump Valve
2.on wire # 28B at
Sense Line Dump Valve
Should read 10-12 volts
If low or no reading
Repair or replace
Sense Line Dump Valve
and/or wiring
TB 37
SECTION TWO
HYDRAULICS DIAGNOSTICS
Inspect
Sense Line Check
Valve
Remove and inspect Sense
Line Check Valve from
Main Hydraulic Valve
Valve should operate
freely.
If Ok
Return to step 1
If not
Replace
Sense Line Check Valve
Step 3
Troubleshooting Guide
43
TB 37
SECTION TWO
HYDRAULICS DIAGNOSTICS
Hydraulic pump
stays on stroke
Inspect
Pump
Compensator
Valve
Remove hose from
compensator. Recheck
pressure on Pump.
If
goes
off
stroke
Check seals on
Sense Line Dump
Valve
If stays on stroke
Repair or replace
Pump Compensator
Repair or replace
Sense Line Dump Valve
If bad
Step 1
Step 1
Hydraulic oil
overheats
during operation
Switch
Manual Overrides
to the On position
Inspect
Functions Valve
Heating stops
Heating
continues
Repair or replace
Functions Valve
Repair or replace
Hosing
Troubleshooting Guide
44
TB 37
SECTION TWO
HYDRAULICS DIAGNOSTICS
Hydraulic functions
are sluggish
Inspect
Engine RPM
Go to step 2
If correct
RPM
Use a Tachometer to
measure Engine RPM
Should read:
Ford - 1050 RPM at Low
2100 RPM at Mid
2800 RPM at High
Deutz -1200 RPM at Low
2800 RPM at High
If not
Adjust
Throttle Actuator
Step 1
Step 2
Inspect
Pump Pressure
Remove gauge
and
Go to step 3
If
300 psi
Install 1000 psi
pressure gauge at
Test Port.
Set engine for idle
and measure standby
pressure.
Should read 300 psi
If low or no reading
Adjust
Pump Compensator
Troubleshooting Guide
45
TB 37
SECTION TWO
HYDRAULICS DIAGNOSTICS
Inspect
Accumulator
Measure the charge
on the Accumulator
Should be 750 to 800 psi
If
750 to 800 psi
If low or no reading
Recharge
Accumulator
Go to step 4
Step 3
Step 4
Inspect
Flow from Pump
Remove gauges
and
Return to step 1
If
12 to
14 gpm
and
300 psi
With chassis raised
(all wheels off the ground)
and adequately supported,
1.Install a Flowmeter on
the discharge side of
pump.
2.Install a 1000 psi
pressure gauge at Test
Port on Accumulator.
Start engine and turn
Throttle Switch to high.
Activate drive function
full on.
Flowmeter should read
12 to 14 gpm and
pressure gauge should
read 300 psi
If low or no reading
Adjust
Flow Ajustment
Troubleshooting Guide
46
TB 37
SECTION TWO
HYDRAULICS DIAGNOSTICS
Hydraulic pump will
not build pressure
Inspect
Pump
Compensator
Valve
Go to step 2
If low
or no
reading
Remove hoses from
Sense Line Dump Valve
to Compensator Valve
and reattach to
Pressure Line. Using a
5000 psi pressure gauge
check pressure.
Should read 2800 psi
If 2800 psi
Remove gauge and
check seals on
Sense Line Dump Valve
If bad
Repair or replace
Sense Line Dump Valve
Step 1
Step 2
Remove
Main Hydraulic Pump
visually check
Pump Coupling
Inspect
Pump Coupling
If bad
Ok
Repair or replace
Pump Coupling
Repair or replace
Compensator
and/or
Main Hydraulic Pump
Troubleshooting Guide
47
TB 37
SECTION TWO
HYDRAULICS DIAGNOSTICS
Hydraulic pump will not
build enough pressure
Inspect
Pump
Compensator
Valve
Go to step 2
If low
or no
reading
Remove hoses from
Sense Line Dump Valve
to Compensator Valve
and reattach to
Pressure Line. Using a
5000 psi pressure gauge
check pressure.
Should read 2800 psi
If 2800 psi
Remove gauge and
check seals on
Sense Line Dump Valve
If bad
Repair or replace
Sense Line Dump Valve
Step 1
Step 2
Inspect
Sense Line Dump
Valve
Check seals on
Sense Line Dump
Valve
If bad
Repair or replace
Sense Line Dump
Valve
If
10-12V
Using meter set to read
voltage, activate Ground
Control Switch and
measure voltage
1. On wire #28B between
Terminal Strip in
Junction Box and
Sense Line Dump Valve
2. On wire # 28B at
Sense Line Dump
Valve
Should read 10-12 volts
If low or no reading
Repair or replace
Sense Line Dump Valve
wiring
Troubleshooting Guide
48
TB 37
SECTION TWO
HYDRAULICS DIAGNOSTICS
Flow from hydraulic
pump is too low
Inspect
Flow Adjustment
on Main Hydraulic
Pump
Visually check Flow
Adjustment Screw on Main
Hydraulic Pump
Screw should extend
between 3/4" and 7/8"
from face of pump
Reset
Flow Adjustment on Main
Hydraulic Pump
Step 1
Step 1
Flow from
hydraulic pump
is too high
(kills engine)
Troubleshooting Guide
Inspect
Flow Adjustment
on Main Hydraulic
Pump
Visually check Flow
Adjustment Screw on Main
Hydraulic Pump
Screw should extend
between 3/4" and 7/8"
from face of pump
Reset
Flow Adjustment on Main
Hydraulic Pump
49
TB 37
SECTION THREE:
STEERING SYSTEM DIAGNOSTICS
SECTION THREE
STEERING SYSTEM DIAGNOSTICS
Chart 1
Step 1
Machine will not
steer
Inspect
Switch for Blocking Valve
Ground Signal (at steer Switch)
Step 2
OK
Inspect
Blocking Valve Relay and Relay
Wiring
Step 3
Go to Page
57
OK
Inspect
Tow Package Float Valve
Troubleshooting Guide
Go to Page
56
OK
Inspect
Center Post
Step 8
Go to Page
56
OK
Inspect
Steer Control Valve
Step 7
Go to Page
55
OK
Inspect
Steer Switch (Left)
Step 6
Go to Page
55
OK
Inspect
Steer Switch (Right)
Step 5
Go to Page
54
OK
Inspect
Blocking Valve
Step 4
Go to Page
54
53
Go to Page
57
TB 37
SECTION THREE
STEERING SYSTEM DIAGNOSTICS
Machine will not steer
Note:
At this point the manual
override may also be
use to isolate
the solenoid, however
use caution as the
machine will be moving.
Inspect
Switch for Blocking
Valve Ground
Signal (at steer
Switch)
Go to step 2
If
continuity
Using a meter set to read
continuity, activate Steer
Switch and check
for ground
1. on wire #100 between
Steer Switch and
Junction Box
2. at wire #100 in
Junction Box
Should show continuity to
ground
If no continuity
Replace
Steer Switch
and/or
Steer Switch wiring
Step 1
Step 2
Inspect
Blocking Valve
Relay and Wires
Go to step 3
If
continuity
Using a meter set to read
continuity, activate Steer
Switch and
check for ground
1. on wire #100 between
Terminal Strip in
Junction Box and
Relay
2. on wire #100 entering
Relay
If no continuity
Repair or replace
Blocking Valve Relay
and/or
Blocking Valve Relay wiring
Troubleshooting Guide
54
TB 37
SECTION THREE
STEERING SYSTEM DIAGNOSTICS
Note:
At this point the manual
override may also be
use to isolate
the solenoid, however
use caution as the
machine will be moving.
Inspect
Blocking Valve
Visually check Blocking
Valve Cartridge for
binding
Should normally be open.
If
Ok
If stuck
Repair or replace
Blocking Valve Cartridge
Go to step 4
Step 3
Step 4
Inspect
Steer Switch
(Right)
Go to step 5
If
10-12V
Using a meter set to
read voltage, activate
Steer Switch Right and
measure voltage
1. on wire #20 between
Steer Switch and Steer
Control Valve
2. on wire #20 at Steer
Control Valve
Should read 10-12 volts
If low or no reading
Replace
Steer Switch (Solenoid)
and/or
Steer Micro (Solenoid)
wiring
Troubleshooting Guide
55
TB 37
SECTION THREE
STEERING SYSTEM DIAGNOSTICS
Inspect
Steer Switch (Left)
During activation of
steering function the
machine will be moving.
Go to step 6
If
10-12V
Using a meter set to
read voltage, activate
Steer Switch Left and
measure voltage
1. on wire #19 between
Steer Switch (Left) and
Steer Control Valve
2. on wire #19 at Steer
Control Valve
Should read 10-12 volts
If low or no reading
Replace
Steer Switch (Solenoid)
and/or
Steer Switch (Solenoid)
wiring
Step 5
Step 6
Inspect
Steer Control
Valve
Activating
Manual Overrides and
check pressure
Should be 1500 psi
If approx.
1500 psi
Go to step 7
Troubleshooting Guide
56
If lower than 1500 psi
Readjust to 1500 psi
TB 37
SECTION THREE
STEERING SYSTEM DIAGNOSTICS
During activation of
steering function the
machine will be moving.
Inspect
Center Post
Repair or replace
Steer Cylinder
Note: Machines
with optional
Tow Package
go to step 8
If
reading
is
normal
Remove hoses leading
to Steer Cylinder Plug
hoses and
cap the Steer Cylinder.
While activating
steering function,
check for 1500 psi at
the pump pressure Test
Port
If reading is abnormal
Repair or replace
Center Post
Step 7
Step 8
Inspect
Tow Package Float
Valve
Troubleshooting Guide
57
Refer to Chapter 12
Accessories Diagnostics
TB 37
SECTION FOUR:
DRIVE SYSTEM DIAGNOSTICS
SECTION FOUR
DRIVE SYSTEM DIAGNOSTICS
Chart 1
Drive system is not
operational with
controller in either
direction
Step 1
Inspect
Foot Switch
Step 2
OK
Inspect
Drive Circuit Breaker (3 amp)
Step 3
Go to Page
65
OK
Inspect
Controller Circuit Board and S1
Micro Switch Wiring
Step 4
Go to Page
66
OK
Inspect
S1 Micro-Switch (in Controller)
Step 5
Go to Page
66
OK
Inspect
Controller Circuit Board
Step 6
Step 7
Go to Page
69
OK
Inspect
Center Post
Step 11
Go to Page
68
OK
Inspect
Drive Control Valve
Step 10
Go to Page
68
OK
Inspect
Drive Solenoid
Step 9
Go to Page
67
OK
Inspect
S2 Micro-Switch (in Controller)
Step 8
Go to Page
67
OK
Inspect
Potentiometer
Go to Page
69
OK
Inspect
Shuttle Valve Portion of Dual
Counterbalance Valve
Troubleshooting Guide
Go to Page
65
61
Go to Page
70
TB 37
SECTION FOUR
DRIVE SYSTEM DIAGNOSTICS
Chart 2
Step 1
No forward drive
(reverse ok)
Inspect
S2 Micro-Switch
(in Drive Controller)
Step 2
OK
Inspect
Drive Controller Circuit Board
Step 3
Go to Page
71
OK
Inspect
Solenoid
(Drive Forward on Control Valve)
Step 4
Go to Page
71
Go to Page
72
OK
Inspect
Dual Counterbalance Cartridge
Go to Page
72
Chart 3
Step 1
No reverse drive
(forward ok)
Inspect
S2 Micro-Switch
(in Drive Controller)
Step 2
OK
Inspect
Drive Controller Circuit Board
Step 3
Go to Page
74
OK
Inspect
Dual Counterbalance Cartridge
Troubleshooting Guide
Go to Page
73
OK
Inspect
Solenoid Valve
(Drive reverse on Control Valve)
Step 4
Go to Page
73
62
Go to Page
74
TB 37
SECTION FOUR
DRIVE SYSTEM DIAGNOSTICS
Chart 4
Step 1
Drive high range
not operating
Inspect
Drive Low/High Range Switch
Step 2
OK
Inspect
Boom Position and/or
Boom Limits Switch
Step 3
Go to Page
76
OK
Inspect
Selector Spool in Transmission
Package
Step 5
Go to Page
75
OK
Inspect
Range Valve
Step 4
Go to Page
75
Go to Page
76
OK
Inspect
Power to R Terminal
Go to Page
77
Inspect
Boom Limits Switch
Go to Page
78
Chart 5
Machine drives at
full speed with
platform raised
and/or extended
Step 1
Step 2
OK
Inspect
Range Valve
Go to Page
78
Inspect
Brake Pressure
Go to Page
79
Chart 6
Step 1
Brakes will not
release
Troubleshooting Guide
63
TB 37
SECTION FOUR
DRIVE SYSTEM DIAGNOSTICS
Chart 7
Only one wheel
turns
(2 wheel drive)
Step 1
Inspect
Case Drain
Step 2
Go to Page
80
OK
Inspect
Flow Divider
Go to Page
80
Inspect
Case Drain
Go to Page
81
Chart 8
One wheel turns
faster than other
(2 wheel drive)
Step 1
Step 2
OK
Inspect
Flow Divider
Troubleshooting Guide
64
Go to Page
81
TB 37
SECTION FOUR
DRIVE SYSTEM DIAGNOSTICS
Drive system is
non-operational
with controller in
either direction
Inspect
Foot switch
Go to step 2
If
10-12V
Using a meter set to
read voltage, activate
Foot Switch and
measure voltage
1. on wire #9 between
Foot Switch and Drive
Circuit Breaker
2. at 3 amp Drive
Circuit Breaker
Should read 10-12 volts
If low or no voltage
Replace
Foot Switch and/or
Foot Switch wiring
Step 1
Step 2
Inspect
Drive Circuit
Breaker (3 amp)
Go to step 3
If
10-12V
Using a meter set to
read voltage, activate
Foot Switch and
measure voltage
1. on wire #69 between
Circuit Breaker and
Drive Controller
2. at positive (+) post of
Drive controller
Should read 10-12 volts
If low or no voltage
Replace
Foot Switch and/or
Foot Switch wiring
Troubleshooting Guide
65
TB 37
SECTION FOUR
DRIVE SYSTEM DIAGNOSTICS
Inspect
Controller Circuit
Board and S1
Micro-Switch
Wiring
Go to step 4
If
10-12V
Using a meter set to
read voltage, activate
Foot Switch and
measure voltage
1. on red wire from
Circuit Board to
S1 Micro-Switch
2. at red wire of
S1 Micro-Switch
Should read 10-12 volts
If low or no voltage
Replace
Circuit Board
and/or
S1 Micro-Switch wiring
Step 3
Step 4
Inspect
S1 Micro-Switch
(in Controller)
If lit
If not lit
Go to step 5
Troubleshooting Guide
Replace
S1 Micro-Switch
(in Controller)
and/or
S1 Micro-Switch
wiring
If low
or no
voltage
Go to step 5
If
10-12V
66
Move controller handle in
either direction and
observe red LED on
Circuit Board Controller
Using a meter set to
read voltage, step on
Foot Switch and
activate Controller,
measure voltage
1. on black wire between
S1 Micro-Switch and
Controller Circuit Board
2. at point where black
wire from S1 Switch
enters Controller Circuit
Board
Should read 10-12 volts
TB 37
SECTION FOUR
DRIVE SYSTEM DIAGNOSTICS
Inspect
Controller Circuit
Board
Go to step 6
If
10-12V
Using a meter set to
read voltage, step on
Foot Switch and
activate Controller,
measure voltage
1. on green wire to
Potentiometer from
Controller Circuit Board
2. on wire between
Controller Circuit Board
and Potentiometer
Should read 10-12 volts
If low or no voltage
Replace
Controller Circuit Board
and/or
Controller Circuit Board
wiring
Step 5
Step 6
Inspect
Potentiometer
Go to step 7
continuity
Replace
Potentiometer
and/or
Potentiometer
wiring
Troubleshooting Guide
67
Using a meter set to ohms,
measure reading across
1. green wire and purple
wire between Controller
Circuit Board and
Potentiometer
2. green wire and orange
wire between Controller
Circuit Board and
Potentiometer
Reading should vary
according to Controller
movement
If no reading
No
continuity
Check continuity on wire
between Controller Circuit
Board and Potentiometer
TB 37
SECTION FOUR
DRIVE SYSTEM DIAGNOSTICS
Inspect
S2 Micro-Switch
(in Controller)
Check continuity
on blue wire and
on white wire
between Controller
Circuit Board and
S2 Micro-Switch
Machine function will be
moving when manual
override is activated.
If no
reading
No Continuity
Continuity
Replace
S2 Micro-Switch
and/or
S2 Micro-Switch
wiring
Using a meter set to
read voltage, step on
Foot Switch and activate
Controller, perform the
following:
1. While activating
controller in forward
mode measure
proportional voltage at
Controller Circuit Board
where white wire enters
from S2 Micro-Switch
2. While activating
Controller in reverse
mode measure
proportional voltage at
Controller Circuit Board
where blue wire enters
from S2 Micro-Switch
Go to step 8
Reading should vary
according to amount of
reverse movement
Step 7
Step 8
Inspect
Drive Solenoid
Go to step 9
If
functions
are
normal
Push Manual Override
while activating various
controller functions and
check operation.
If functions are abnormal or erratic
Replace
Drive Section
Control Valve
Troubleshooting Guide
68
TB 37
SECTION FOUR
DRIVE SYSTEM DIAGNOSTICS
Inspect
Drive Control
Valve
Remove gauge
and
Go to step 10
If functions
are normal
Remove hoses from drive
section of Control Valve.
Plug the hoses and cap
valve. Install a 5000 psi
pressure gauge to
Pump Test Port.
While activating drive
control function, check
pressure.
Should read 2800 psi
(while activating function)
If functions are abnormal or erratic
Replace
Valves on Drive Section
of Control Valve
Step 9
Step 10
Inspect
Center Post
Remove gauge
and
Go to step 11
If pressures
are normal
Remove hoses at V1 and
V2 ports of Dual
Counterbalance Valve.
Plug hoses and cap valve.
Install a 5000 psi pressure
test gauge to
Pump Test Port
While activating drive
control function, check
pressure.
Should read 2800 psi
(while activating function)
If pressures are abnormal or erratic
Repair or replace
Center Post
Troubleshooting Guide
69
TB 37
SECTION FOUR
DRIVE SYSTEM DIAGNOSTICS
Inspect
Shuttle Valve
Portion of Dual
Counterbalance
Valve
Install a 5000 psi pressure
test gauge to BR port of
Dual Counterbalance
Valve. Note if pressure is
equal to drive pressure.
equal pressure
Return to step 1
unequal pressure
Replace
Shuttle Valve (in Dual
Counterbalance Valve)
Step 11
Troubleshooting Guide
70
TB 37
SECTION FOUR
DRIVE SYSTEM DIAGNOSTICS
No forward drive
(Reverse Ok)
Inspect
S2 Micro-Switch
(in Drive
Controller)
Go to step 2
Replace
S2 Micro-Switch
and/or
S2 Micro-Switch
wiring
If
normal
Using a meter set to
read voltage, activate
function and measure
proportional voltage at
Controller Circuit Board
at point where blue wire
from S2 Micro-Switch
enters.
Reading should vary
according to controller
movement.
If low or no reading
no continuity
Check continuity on blue
wire between S2 MicroSwitch and Controller
Circuit Board
If
normal
Using a meter set to
read voltage, activate drive
function and measure
proportional voltage at
Terminal A of
Circuit Board.
Reading should vary
according to controller
movement.
Step 1
Step 2
Inspect
Drive Controller
Circuit Board
Go to step 3
If no or erratic reading
Replace
Drive Controller Circuit
Board
Troubleshooting Guide
71
TB 37
SECTION FOUR
DRIVE SYSTEM DIAGNOSTICS
Machine function will be
moving when manual
override is activated.
Using a meter set to read
voltage. While activating
forward function, measure
proportional voltage at wire
#17 on Drive section of
Control Valve.
Reading should vary
according to controller
movement.
Inspect
Solenoid Valve
(Drive forward
on Control Valve)
If no reading
Try manual override
Override allows operation
Override
does not
allow
operation
Go to step 4
Replace
Drive Forward Solenoid
Valve and/or
Drive Forward Solenoid
Valve wiring
Step 3
Step 4
Inspect
Dual
Counterbalance
Valve Cartridge
Using a 5000 psi pressure
test gauge activate drive
function and check system
pressure at hose entering
port M1 on Counterbalance
Valve
If no pressure reading
Replace the
Dual Counterbalance Valve
Cartridge tested
Troubleshooting Guide
72
TB 37
SECTION FOUR
DRIVE SYSTEM DIAGNOSTICS
No reverse drive
(Forward Ok)
Inspect
S2 Micro-Switch
(in Drive
Controller)
Go to step 2
Replace
S2 Micro-Switch
and/or
S2 Micro-Switch
wiring
If
normal
Using a meter set to
read voltage, activate
reverse function and
measure proportional
voltage at Controller
Circuit Board at point
where white wire from
S2 Micro-Switch enters.
Reading should vary
according to controller
movement.
If low or no reading
No continuity
Check continuity on white
wire between S2 MicroSwitch and Controller
Circuit Board
If
normal
Using a meter set to
read voltage, activate
reverse function
and measure
proportional voltage at
Terminal B of
Controller Circuit Board
Reading should vary
according to controller
movement
Step 1
Step 2
Inspect
Drive Controller
Circuit Board
Go to step 3
If no or erratic reading
Replace
Drive Controller Circuit
Board
Troubleshooting Guide
73
TB 37
SECTION FOUR
DRIVE SYSTEM DIAGNOSTICS
Inspect
Solenoid Valve
(Drive reverse on
Control Valve)
Using a meter set to read
voltage. While activating
reverse function,
measure proportional
voltage at wire #18 on
Drive section of
Control Valve.
Reading should vary
according to controller
movement.
Machine function will be
moving when manual
override is activated.
If no reading
Try manual override
Override allows operation
Override
does not
allow
operation
Go to step 4
Replace
Drive Reverse
Solenoid Valve and/or
Drive Reverse Solenoid
Valve wiring
Step 3
Step 4
Inspect
Dual
Counterbalance
Valve Cartridge
Using pressure test gauge
activate drive function and
check system pressure at
hose entering port M2 on
Counterbalance Valve
If no pressure reading
Replace the
Dual Counterbalance Valve
Cartridge tested
Troubleshooting Guide
74
TB 37
SECTION FOUR
DRIVE SYSTEM DIAGNOSTICS
Drive high range
not operating
Inspect
Drive Low/High
Range Switch
Go to step 2
If low
or no
reading
Using a meter set to
read voltage, measure
voltage on wire #16A going
into the Low/High Drive
Range Switch
Should read 10-12 volts
If 10-12V
Go to step 3
If 10-12V
Measure voltage on
wire #11 coming out of
the Low/High Drive
Range Switch.
Should read 10-12 volts
If low or no reading
Replace
Drive Low/High Range
Switch and/or
Drive Low/High Range
Switch wiring
Step 1
Step 2
Inspect
Boom Position
and/or
Boom Limit Switch
Booms are not positioned
for High Range speed
operations
Boom Limit Switch are
not Adjusted
Repair or replace
Boom Extend Limit
Switch and/or
wiring
Position Booms to fully
retracted and down
position. Adjust Boom
Retract/Down Limit Switch
If no
voltage
Repair or replace
Boom Up Limit
Switch and/or
wiring
Repair or replace
Wiring to Drive
Low/High Range
Switch
Troubleshooting Guide
75
still not operating
Check for 10-12 volts at
wire #70A at Boom
Extend Limit Switch
If no
voltage
If 10-12V
If 10-12V
Check for 10-12 volts on
wire #16A at Boom Up
Limit Switch
TB 37
SECTION FOUR
DRIVE SYSTEM DIAGNOSTICS
Inspect
Range Valve
Using meter set to read
voltage, measure voltage
at Range Valve wire #34.
Should read 10-12 volts
If no reading
If
10-12V
Check for
blockage in Drive
Range Valve
and/or hoses
If
pressure
is low
Repair or replace
Wiring to Range Valve
Using a 5000 psi pressure
gauge, measure pressure
on hose between Range
Valve and Center Post.
Should read Drive Pressure
If Ok
Go to step 4
Step 3
Step 4
Inspect
Selector Spool in
Transmission
Package
Go to step 5
If speeds
are
reached
and
Selector
Spool
is shifting
Verify that Selector Spool is
shifting by checking
drive speed.
Should be 1-1.5 mph.
deactivated
and 2-3 mph. activated.
(3 mph = 100 ft in 22 sec)
If speeds are 1-1.5 and
Selector Spool is not shifting
Repair or replace
Selector Spool in
Transmission Package
Troubleshooting Guide
76
TB 37
SECTION FOUR
DRIVE SYSTEM DIAGNOSTICS
Inspect
Power to R
Terminal
Check connection
on Boom Wire
between Boom
Switches and
Platform
If
low
With Boom retracted and
lowered, use a meter set
to read voltage, measure
voltage at the R Terminal
of Drive Controller
Should read 10-12 volts
If
10-12V
If no reading
Return to step 2
Adjust High Speed Trim Pot
on controller to get
3 mph + 100 ft in 22 sec.
Step 5
Troubleshooting Guide
77
TB 37
SECTION FOUR
DRIVE SYSTEM DIAGNOSTICS
Machine drives at full
speed with platform
raised and/or extended
Inspect
Boom Limits
Switch
Go to step 2
Boom Limits Switch are
sticking or not properly
Adjusted
problem
still
exists
Repair, replace or readjust
Boom Limits Switch
Step 1
Step 2
Inspect
Range Valve
Using a 5000 psi pressure
gauge, measure pressure
on hose between Range
Valve and Center Post
Should read 0 psi
If
0 psi
If Drive pressure
Repair or replace
Range Valve
Check for stuck
Selector Valve on
Transmission Package
Troubleshooting Guide
78
TB 37
SECTION FOUR
DRIVE SYSTEM DIAGNOSTICS
Brakes will not
release
Inspect
Brake Pressure
1. Install a 5000 psi
pressure gauge in BR
Port on Motion Control
Valve
2. Take pressure reading
at Pump Compensator
Readings should be
similar
Repair or replace
Brake Shuttle Valve
Step 1
Troubleshooting Guide
79
TB 37
SECTION FOUR
DRIVE SYSTEM DIAGNOSTICS
Only one wheel turns
(2 wheel drive)
Note:
Make sure Hubs are engaged.
Inspect
Case Drain
Go to step 2
If less
than
.5 gpm
Disconnect existing hose,
install a flowmeter
between existing hose
and Drive Motor.
Should be no more than
.5 gpm while driving
If more than .5 gpm
Repair or replace
Drive Motor
Step 1
Step 2
Inspect
Flow Divider
Repair or replace
as needed
If Ok
Remove Flow Divider from
Drive Control Valve.
Visually check for broken
springs
If bad
Repair or replace Relief
Valve in Drive Control
Valve
Troubleshooting Guide
80
TB 37
SECTION FOUR
DRIVE SYSTEM DIAGNOSTICS
One wheel turns faster
than other (2 wheel drive)
Inspect
Case Drain
Go to step 2
If less
than
.5 gpm
Disconnect existing hose,
install a flowmeter
between existing hose
and Drive Motor.
Should be no more
than .5 gpm
If more than .5 gpm
Repair or replace
Drive Motor
Step 1
Step 2
Inspect
Flow Divider
Repair or replace
as needed
If Ok
Remove Flow Divider from
Drive Control Valve.
Visually check for broken
springs
If bad
Repair or replace Relief
Valve in Drive Control
Valve
Troubleshooting Guide
81
TB 37
SECTION FIVE:
EMERGENCY POWER SYSTEM DIAGNOSTICS
SECTION FIVE
EMERGENCY POWER SYSTEM DIAGNOSTICS
Chart 1
Emergency pump
motor nonoperational
Step 1
Inspect
Battery and Cable Connections
Step 2
OK
Inspect
Emergency Power Switch
Step 3
Go to Page
86
OK
Inspect
Emergency Power Solenoid
and Wiring
Step 4
Go to Page
86
Go to Page
87
OK
Inspect
Emergency Power Unit
Go to Page
87
Inspect
Battery and Cable Connections
Go to Page
88
Chart 2
No functions when
on emergency
power
Step 1
Step 2
OK
Inspect
Emergency Power Pump
Step 3
OK
Inspect
Blocking Valve
Troubleshooting Guide
Go to Page
88
85
Go to Page
89
TB 37
SECTION FIVE
EMERGENCY POWER SYSTEM DIAGNOSTICS
Emergency
pump motor
non-operational
Batteries omit hydrogen
and oxygen elements that
can combine explosively.
Do not smoke or permit
open flames or sparks
when checking batteries
Recharge or
replace
battery(s)
If low or no voltage
Inspect
Batteries
Using a meter
set to read
voltage, check
each battery for
12 volts while
under load
Clean all
connections
If 12V
Check battery
connections
If
corroded
If loose
Tighten all
connections
Step 1
Step 2
Inspect
Emergency Power
Switch
Go to step 3
If
10-12V
Repair or Replace
Emergency Power
Switch Terminal
wiring (wire #6)
and/or
Emergency Power
Solenoid wiring
(wire #6A)
and/or
Emergency Power
Switch
Using a meter set to
read voltage, activate
Emergency Power and
measure voltage
1. on wire #6 of
Emergency Power
Switch
2. at Emergency Power
Solenoid
Should be 10-12 volts
If no reading
Check continuity
1. on wire #6 between
Emergency Power
Switch and Terminal
Strip in Control Box
2. between wire #6 of
Terminal Strip in
Junction Box and wire
#6A at Emergency
Power Solenoid
No continuity
Troubleshooting Guide
86
TB 37
SECTION FIVE
EMERGENCY POWER SYSTEM DIAGNOSTICS
Inspect
Emergency Power
Solenoid
and Wiring
Go to step 4
Repair or Replace
Wiring from Battery
Disconnect Switch
to Emergency
Power Solenoid
and/or
Emergency Power
Unit wiring and/or
Emergency Power
Solenoid
If
10-12V
Using a meter set to read
voltage, measure voltage
1. at Emergency Power
Solenoid and from
Battery Disconnect
Switch
2. activate Emergency
Power Switch and
measure voltage at
Emergency Pump
Motor
Should be 10-12 volts
If no reading
No
continuity
Check continuity
1. on wire between
Battery Disconnect
Switch and Emergency
Power Solenoid
2. on wire between
Emergency Power
Solenoid and Pump
Motor
Step 3
Step 4
Inspect
Emergency Power
Unit
If previous checks have
been performed and found
to be normal, check
Emergency Pump Motor
for internal grounding
condition
Repair or Replace
Emergency Pump Motor
Troubleshooting Guide
87
TB 37
SECTION FIVE
EMERGENCY POWER SYSTEM DIAGNOSTICS
No functions when on
emergency power
Batteries omit hydrogen
and oxygen elements that
can combine explosively.
Do not smoke or permit
open flames or sparks
when checking batteries
Recharge or
replace
battery(s)
If low or no voltage
Inspect
Batteries
Using a meter
set to read
voltage, check
each battery for
12 volts while
under load
Clean all
connections
If 12V
Check battery
connections
If
corroded
If loose
Tighten all
connections
Step 1
Step 2
Inspect
Emergency Power
Pump
Remove gauge
and
Go to step 3
If
Ok
Attach 5000 psi pressure
gauge to discharge
side of Emergency Power
Pump, activate
Emergency Power Pump
and Ground Control Switch
or Foot Switch.
Should read 3000 psi.
If reading is abnormal or erratic
Repair or Replace
Emergency Power Pump
Unit
Troubleshooting Guide
88
TB 37
SECTION FIVE
EMERGENCY POWER SYSTEM DIAGNOSTICS
Inspect
Blocking Valve
Refer back to
Chapter 3, Chart 1
Step 3
If
no voltage
With Ground Control
Switch activated, use a
meter set to read voltage
and measure voltage
on wire #100B to
Blocking Valve Solenoid
Should be 10 to 12 volts
If 10 to 12V
Repair or replace
Blocking Valve Cartridge
Step 3
Troubleshooting Guide
89
TB 37
SECTION SIX:
SWING SYSTEM DIAGNOSTICS
SECTION SIX
SWING SYSTEM DIAGNOSTICS
Chart 1
Step 1
Swings only in
one direction
Inspect
Swing Control Signal Wire
Step 2
Go to Page
96
OK
Inspect
Swing Control Valve
Go to Page
96
Inspect
Foot Switch
Go to Page
97
Chart 2
No response from
swing when
platform controls
are activated
(Ground
Controls Ok)
Step 1
Step 2
OK
Inspect
Swing Switch
Go to Page
97
Inspect
Ground Control Switch
and Wiring
Go to Page
98
Chart 3
No response from
swing when ground
control is activated
Step 1
Step 2
OK
Inspect
Swing Switch
Step 3
OK
Inspect
Swing Valve
Step 4
Go to Page
99
OK
Inspect
Swing Motor and Gear Box
Troubleshooting Guide
Go to Page
98
93
Go to Page
99
TB 37
SECTION SIX
SWING SYSTEM DIAGNOSTICS
Chart 4
Step 1
Swings erratically
in either direction
Activate
Manual Override
Step 2
OK
Inspect
Solenoid
Step 3
Go to Page
100
OK
Inspect
Switch
Step 4
Go to Page
100
Go to Page
101
OK
Inspect
Swing Brake
Go to Page
101
Inspect
Crossover Relief Valve
Go to Page
102
Chart 5
Step 1
Swings faster one
way than other
Step 2
OK
Inspect
Solenoid
Go to Page
102
Inspect
Swing Brake
Go to Page
103
Chart 6
Step 1
Swing Brake
will not hold
Troubleshooting Guide
94
TB 37
SECTION SIX
SWING SYSTEM DIAGNOSTICS
Chart 7
Step 1
Activate
Manual Override
Swings too slow
Step 2
OK
Inspect
Solenoid
Step 3
Go to Page
105
OK
Inspect
Swing Brake Release
Troubleshooting Guide
Go to Page
104
OK
Inspect
Lift/Swing Speed Dial and Valve
Step 4
Go to Page
104
95
Go to Page
105
TB 37
SECTION SIX
SWING SYSTEM DIAGNOSTICS
Swings only in
one direction
When the turn table
rotates clockwise (cw) it
will be moving toward you.
Make sure you have room
to step backward.
Machine function will be
moving when manual
override is activated.
Using meter set to read
voltage, perform the
following:
1. while activating
platform in ccw
direction, measure
voltage on wire #23 at
the Terminal Strip in
the Platform Box
2. while activating
platform in cw direction,
measure voltage on
wire #24 at the
Terminal Strip at
Platform Box
Should be 10-12 volts
Inspect
Swing Control
Signal Wire
Replace Swing
Switch
If no
voltage
If no reading
Check continuity on
1. wire #23 between
Terminal Strip in the
Platform Box and
Swing Control Valve
2. wire #24 between
Terminal Strip in the
Platform Box and
Swing Control Valve
Repair or Replace
Swing Control Valve
wiring
If Ok
Go to step 2
Step 1
No continuity
Step 2
Manually operate
Swing Control Valve
Inspect
Swing Control
Valve
If functioning
improperly
Repair or Replace
Swing Control
Valve
Troubleshooting Guide
96
If functioning properly
Repair or Replace
Swing Control Valve
Solenoid
TB 37
SECTION SIX
SWING SYSTEM DIAGNOSTICS
No response from swing when
platform controls are activated
(Ground Controls Ok)
Inspect
Foot Switch
Go to step 2
If
10-12V
Using a meter set to
read voltage, while
stepping on the Foot
Switch, measure voltage
on wire # 9 at
Swing Switch
Should read 10-12 volts
If no reading
Repair or Replace
Foot Switch and/or
Foot Switch wiring
Step 1
Step 2
Inspect
Swing Switch
Check connection
in Junction Box
If no reading
Using a meter set to
read voltage, while
activating function, check
voltage on Swing Switch to
Junction Box
(wire #23 when swing
is moving in a
counterclockwise direction,
wire #24 when swing
is moving in a
clockwise direction)
Should be 10-12 volts
If no reading
Repair or Replace
Swing Switch
and/or
Swing Switch wiring
Troubleshooting Guide
97
TB 37
SECTION SIX
SWING SYSTEM DIAGNOSTICS
No response from swing
when ground controls are
activated
When the turn table
rotates clockwise (cw) it
will be moving toward you.
Make sure you have room
to step backward.
Inspect
Ground Control
Switch and Wiring
Go to step 2
If
10-12V
Using a meter set to read
voltage, activate swing
function, measure voltage
from Ground Control
Switch to Ground Swing
Switch
Should be 10-12 volts
If no reading
Repair or Replace
Ground Control Switch
and/or
Ground Control Switch
wiring
Step 1
Step 2
Inspect
Swing Switch
Go to step 3
If
10-12V
Using a meter set to
read voltage, while
activating function, check
voltage on Swing Switch to
Swing Valve
(wire #23 when swing
is moving in a
counterclockwise direction,
wire #24 when swing
is moving in a
clockwise direction)
Should be 10-12 volts
If no reading
Repair or Replace
Swing Switch and/or
Swing Switch wiring
Troubleshooting Guide
98
TB 37
SECTION SIX
SWING SYSTEM DIAGNOSTICS
Inspect
Swing Valve
Go to step 4
If
2500 psi
Remove hoses from
Swing Drive Motor.
Plug hoses and cap
motor. While activating
swing function, check
pressure at
Pump Compensator
Pressure should read
2500 psi
If reading is low or erratic
Go to page 104
Step 3
Step 4
Inspect
Swing Motor and
Gear Box
Return to step 1
If
2500 psi
If previous steps have
been made and Swing
Valve checks ok,
check pressure.
If low
Replace
Swing Motor and/or
Gear Box
Troubleshooting Guide
99
TB 37
SECTION SIX
SWING SYSTEM DIAGNOSTICS
Swings erratically in
either direction
Machine function will be
moving when manual
override is activated.
Push in on Manual
Override and observe
swing operation
Activate
Manual Override
If still swings erratically
If ok
Go to step 4
Go to step 2
Step 1
Step 2
Inspect
Solenoid
Supply 12 volts to
Solenoid, check if swing is
operating smoothly
If still swings erratically
If ok
Replace Solenoid
Go to step 3
Troubleshooting Guide
100
TB 37
SECTION SIX
SWING SYSTEM DIAGNOSTICS
Inspect
Swing Switch
When the turn table
rotates clockwise (cw) it
will be moving toward you.
Make sure you have room
to step backward.
Using a meter set to
read voltage, while
activating function, check
voltage on Swing Switch to
Swing Valve
(wire #23 when swing
is moving in a
counterclockwise direction,
wire #24 when swing
is moving in a
clockwise direction)
Should be 10-12 volts
If no reading
Repair or Replace
Swing Switch
and/or
Swing Switch wiring
Step 3
Step 4
Inspect
Swing Brake
Install 5000 psi pressure
gauge into Swing Brake
Line, while activating
function, check pressure.
Should maintain steady
pressure above 350 psi
If ok
Repair or replace
Swing Brake and/or
Gear Box
Troubleshooting Guide
101
TB 37
SECTION SIX
SWING SYSTEM DIAGNOSTICS
Swings faster one way
than other
When the turn table
rotates clockwise (cw) it
will be moving toward you.
Make sure you have room
to step backward.
Inspect
Crossover Relief
Valve
Swap Crossover Relief
Valves, check for problem
in opposite direction
If still swings faster
If ok
Repair or replace
Crossover Relief Valve
Go to step 2
Step 1
Step 2
Inspect
Solenoid
Supply 12 volts to
Solenoid, check if swing is
operating equally
If still swings faster
Replace Solenoid
Troubleshooting Guide
102
TB 37
SECTION SIX
SWING SYSTEM DIAGNOSTICS
Swing brake will
not hold
Visually check
Swing Brake
Inspect
Swing Brake
If damaged
Repair or replace
Swing Brake
Check Spools on
Control Valve for
blocked ports
If 0 psi
If Ok
If blocked
Install 5000 psi pressure
gauge into Swing Brake
Line, check pressure.
Should be 0 psi
If above 0 psi
If blocked
Repair or replace
as needed
If Ok
If
damaged
Inspect Counter Balance
Cartridge for proper
operation and/or damage
to O-rings
Check return Line
and filter for
blockage
Step 1
Troubleshooting Guide
103
TB 37
SECTION SIX
SWING SYSTEM DIAGNOSTICS
Swings too slow
Machine function will be
moving when manual
override is activated.
Activate
Manual Override
Push in on Manual
Override and observe
swing function for faster
movement
If
Swings
faster
If still swings slow
Go to step 3
Go to step 2
Step 1
Step 2
Inspect
Solenoid
If still
swings slow
Go to step 3
Supply 12 volts to
Solenoid, check if swing is
operating normally
If swing is normal
Repair or replace
Wiring to Valve
Troubleshooting Guide
104
TB 37
SECTION SIX
SWING SYSTEM DIAGNOSTICS
Inspect
Lift/Swing Speed
Dial and Valve
Visually check Speed Dial
in platform Control Box for
fast speed.
Dial should be set to fast
If Ok
Replace Dial
If no
voltage
Repair or replace
as needed
If bad
Remove Valve,
visually check to
insure that it is
moving when
power is applied
and that O'Rings
are ok.
While activating swing
function, use a meter set to
read voltage, measure
voltage on wire #108B at
Speed Dial.
Should read 10-12 volts
If 10-12V
If 10-12V
While activating Swing
function, measure voltage
on wire #108 at Lift/Swing
Speed Valve.
Should read 10-12 volts
If Ok
If no voltage
Go to step 4
Repair wire to Valve
Inspect
Swing Brake
Release
Install 5000 psi pressure
gauge into Swing Brake
Line, while activating
function check pressure.
Should maintain steady
pressure above 350 psi
Step 3
Step 4
If still swings slow
If ok
Return to step 1
Repair or replace Swing
Brake
Troubleshooting Guide
105
TB 37
SECTION SEVEN:
PLATFORM ROTATION SYSTEM DIAGNOSTICS
SECTION SEVEN
PLATFORM ROTATION SYSTEM DIAGNOSTICS
Chart 1
Step 1
The platform rotate
does not operate
Inspect
Platform Rotate Switch
Step 2
Go to Page
110
OK
Inspect
Platform Rotator Motor
Go to Page
110
Inspect
Platform Actuator
Go to Page
111
Chart 2
Step 1
Platform rotates
itself
Step 2
OK
Inspect
Holding Valves
Troubleshooting Guide
109
Go to Page
111
TB 37
SECTION SEVEN
PLATFORM ROTATION SYSTEM DIAGNOSTICS
Platform rotate
does not
operate
Inspect
Platform Rotate
Switch
If
10-12V
Go to step 2
If no reading
Check continuity on
1. wire #26 between
Terminal Strip in the
Junction Box and
Platfrom Rotation Motor
2. wire #27 between
Terminal Strip in the
Junction Box and
Platfrom Rotation Motor
Repair or replace
Platform Rotate Switch
and/or wiring
No continuity
Step 1
Step 2
Using meter set to read
voltage, perform the
following:
1. While activating
platform in ccw
direction, measure
voltage on wire #26 at
the Rotation Control
Valve
2. While activating
platform in cw direction,
measure voltage on
wire #27 at the Rotation
Control Valve
Should read 10-12 volts
Inspect
Platform Rotator
Motor
Change Platform
Rotator Motor
If
continuity
does not
exists
Using meter set to read
ohms, check for continuity
through wire on Motor
Should show continuity
If continuity does exists
Check for ground on
Platfrom Rotator Switch
Repair or replace
as needed
Troubleshooting Guide
110
TB 37
SECTION SEVEN
PLATFORM ROTATION SYSTEM DIAGNOSTICS
Platform rotates itself
Inspect
Platform Actuator
Check Key by removing the
coverplate on Actuator.
Visually check for damage
If no damage
If damaged
Go to step 2
Repair or replace
Platform Actuator
Inspect
Holding Valves
Visually inspect
Holding Valves
Step 1
Step 2
Repair or replace
as needed
Troubleshooting Guide
111
TB 37
SECTION EIGHT:
PLATFORM LEVELING SYSTEM DIAGNOSTICS
SECTION EIGHT
PLATFORM LEVELING SYSTEM DIAGNOSTICS
Chart 1
Platform will not
maintain level as
boom
raises or lowers
Step 1
Inspect
Hydraulic Oil Temperature
Step 2
Go to Page
117
OK
Inspect
Holding Valves
Go to Page
117
Inspect
Holding Valves in
Slave Level Cylinder
Go to Page
118
Inspect
Ground Control Switch
Go to Page
119
Chart 2
Platform will not
maintain level with
machine off
Step 1
Chart 3
Platform level will
not work from
ground control
Step 1
Step 2
OK
Inspect
Level Switch
Step 3
OK
Inspect
Blocking Valve Relay
Step 4
Go to Page
120
OK
Inspect
Blocking Valve
Troubleshooting Guide
Go to Page
119
115
Go to Page
120
TB 37
SECTION EIGHT
PLATFORM LEVELING SYSTEM DIAGNOSTICS
Chart 4
Platform level will
not work from
platform control
(Ground Control Ok)
Step 1
Inspect
Platform Level Switch
Go to Page
121
Chart 5
Step 1
Platform level
up function is
inoperative
Activate
Manual Override
Step 2
OK
Go to Page
122
OK
Inspect
Solenoid Valve
Go to Page
122
Inspect
Pressure to Cylinder
Go to Page
123
Inspect
Manual Override
Go to Page
124
Step 3
Chart 6
Step 1
Platform level
down function is
inoperative
Step 2
OK
OK
Inspect
Solenoid Valve
Go to Page
124
Inspect
Pressure to Cylinder
Go to Page
125
Step 3
Troubleshooting Guide
116
TB 37
SECTION EIGHT
PLATFORM LEVELING SYSTEM DIAGNOSTICS
The platform does not
maintain level as boom
raises or lowers
Inspect
Hydraulic Oil
Temperature
Go to step 2
Hydraulic Oil is cold
If cold
If problem
still exists
Cycle the boom a few
times to warm up the
hydraulic oil
Step 1
Step 2
Inspect
Holding Valves
between Master
Level Cylinder
and Tank
With platform level and
boom fully down, remove
the hoses to Level Control
Valve and cap
Valve and plug hoses.
Raise boom 5 ft. and note
the Platform Leveling
System.
If Level System
performs
abnormally
If Level System performs normally
Repair or replace
Holding Valves in Control
Package
Repair or replace
Seals in Master Leveling
System
Troubleshooting Guide
117
TB 37
SECTION EIGHT
PLATFORM LEVELING SYSTEM DIAGNOSTICS
The platform will not
maintain level with
machine off
Place a safe work load
in platform and
remove the hoses to
Slave Level Cylinder
Observe the Platform.
Inspect
Holding Valves in
Slave Level
Cylinder
If oil leaks and platform drifts
If no oil leaks
but platform
still drifts
Repair or replace
Holding Valves
Repair or replace
Level Cylinder
Step 1
Troubleshooting Guide
118
TB 37
SECTION EIGHT
PLATFORM LEVELING SYSTEM DIAGNOSTICS
Platform level will not
work from ground control
Inspect
Ground Control
Switch
Go to step 2
Repair or replace
Ground Control
Switch
and/or
Ground Control
Switch wiring
If
10-12V
Using meter set to read
voltage, activate Ground
Control Switch and
measure voltage on
wire #28 entering Platform
Level Switch
Should read 10-12 volts
If no reading
No
continuity
Check continuity on wire
#28 between Ground
Control Switch and
Platform Level Switch
Step 1
Step 2
Inspect
Level Switch
Go to step 3
If
10-12V
Using meter set to read
voltage, activate
Level Down and measure
voltage on
wire #13 at Junction Box
Should read 10-12 volts
If no reading
Repair or replace
Platform Level Switch
and/or
Platform Level Switch
wiring to Junction Box
Troubleshooting Guide
119
TB 37
SECTION EIGHT
PLATFORM LEVELING SYSTEM DIAGNOSTICS
Inspect
Blocking Valve
Relay
While activating Level,
Switch check for continuity
to ground on wire 100
No
continuity
Continuity
Continuity
Check for continuity on
wire 100 from
Level Switch to
Blocking Valve Relay
Repair or replace
Level Switch
Go to step 4
No continuity
Repair or replace
Wire #100
Step 3
Step 4
Inspect
Blocking Valve
If 10-12V
Replace
Blocking Valve
Relay
Using a meter set to
read voltage, measure
voltage on wire #100B to
Blocking Valve
Should read 0 volts
If 0 volts
Remove Blocking Valve
from Control Valve, visually
check Valve.
Valve should be open.
If bad
Replace
Blocking Valve
Troubleshooting Guide
120
TB 37
SECTION EIGHT
PLATFORM LEVELING SYSTEM DIAGNOSTICS
Platform level will not work
from platform control
(Ground Control Ok)
Inspect
Platform Level
Switch
Replace
Foot Switch
If low
or no
voltage
Using a meter
set to read voltage,
measure voltage on
wire #9 entering
Platform Level Switch
Should read 10-12 volts
If 10-12V
Replace
Level Switch
If low
or no
voltage
Measure voltage on wires
#12 and #13 leaving
Platform Level Switch
Should read 10-12 volts
If 10-12V
Replace
Switch
If
continuity
does not
exists
Using a meter set to read
ohms, check for continuity
on wire #108B to ground
If continuity exists
Repair Wire
If
continuity
does not
exists
Check for continuity on
wire #108B to Lower
Control Box
If continuity exists
Return to step 1
Step 1
Troubleshooting Guide
121
TB 37
SECTION EIGHT
PLATFORM LEVELING SYSTEM DIAGNOSTICS
Platform level up
function is inoperative
Machine function will be
moving when manual
override is activated.
Push in on Manual
Override and observe
Platform level up function
Activate
Manual Override
If problem
still exists
If ok
Go to step 2
Go to step 3
Step 1
Step 2
Using a meter
set to read voltage,
measure voltage on wire
#13 between Level Switch
and Solenoid Valve
Should be 10-12 volts
Inspect
Solenoid Valve
If
10-12V
If no reading
Repair or replace
wire #13
Repair or replace
Solenoid Valve
Troubleshooting Guide
122
TB 37
SECTION EIGHT
PLATFORM LEVELING SYSTEM DIAGNOSTICS
Install 5000 psi pressure
gauge at Port 2 of Slave
Level Cylinder. Activate
function and measure
pressure to Slave Level
Cylinder.
Should read 2000 psi
when fully extended.
Inspect
Pressure to
Cylinder
Repair or replace
Slave Level
Cylinder
Repair or replace
Relief Valve in
Control Valve
If low or no reading
If
2000 psi
If low
or no
reading
Remove hose from Port 1
on Slave Level Cylinder,
plug hose and cap Slave
Level Cylinder.
Recheck pressure
Should read 2000 psi
when fully extended.
Step 3
Troubleshooting Guide
123
TB 37
SECTION EIGHT
PLATFORM LEVELING SYSTEM DIAGNOSTICS
Platform level down
function is inoperative
Machine function will be
moving when manual
override is activated.
Inspect
Manual Override
Push in on Manual
Override and observe
Platform Level down
function
If problem
still exists
If ok
Go to step 2
Go to step 3
Step 1
Step 2
Using a meter
set to read voltage,
measure voltage on wire
#12 between Level Switch
and Solenoid Valve
Should be 10-12 volts
Inspect
Solenoid Valve
If
10-12V
If no reading
Repair or replace
Wire #12
Repair or replace
Solenoid Valve
Troubleshooting Guide
124
TB 37
SECTION EIGHT
PLATFORM LEVELING SYSTEM DIAGNOSTICS
Inspect
Pressure to
Cylinder
Install 5000 psi pressure
gauge at Port 1 of Slave
Level Cylinder. Activate
function and measure
pressure to Slave Level
Cylinder.
Should read 2000 psi
when fully retracted.
Repair or replace
Slave Level
Cylinder
If low or no reading
Repair or replace
Relief Valve in
Control Valve
If
2000 psi
If low
or no
reading
Remove hose from Port 2
on Slave Level Cylinder,
plug hose and cap Slave
Level Cylinder.
Recheck pressure
Should read 2000 psi
when fully retracted.
Step 3
Troubleshooting Guide
125
TB 37
SECTION NINE:
BOOM ELEVATION SYSTEM DIAGNOSTICS
SECTION NINE
BOOM ELEVATION SYSTEM DIAGNOSTICS
Chart 1
Boom raises but
will not stay
elevated
Step 1
Inspect
Manual Bleed Down
Go to Page
130
OK
Step 2
Inspect
Holding Valve
Go to Page
130
OK
Step 3
Inspect
Seals in Cylinder
Go to Page
131
Inspect
Boom Lift Switch
Go to Page
132
Chart 2
Boom will not
raise from
platform control
(Ground Control
Ok)
Step 1
OK
Step 2
Inspect
Lift/Swing Speed Valve
Go to Page
132
Inspect
Boom Lift Switch
Go to Page
133
Chart 3
Boom will not
raise from
ground control
Step 1
Step 2
OK
Inspect
Lift/Swing Speed Valve
Step 3
OK
Inspect
Lift Control Valve
Troubleshooting Guide
Go to Page
133
129
Go to Page
134
TB 37
SECTION NINE
BOOM ELEVATION SYSTEM DIAGNOSTICS
Boom raises but will
not stay elevated
Inspect
Manual Bleed
Down
Turn Manual Bleed Down
Valve clockwise until
valve is closed
Problem still exist
Repair or replace
Manual Bleed
Down
Leakage
Raise boom approximately
2 ft. and mark Lift Cylinder.
Remove hose from port #4
on Lift Cylinder. Observe oil
leakage.
Problem still exist
Go to step 2
Step 1
Step 2
Inspect
Holding Valve
Go to step 3
Problem
still exist
Raise boom approximately
2 ft, remove hose to
#2 port on Lift Cylinder,
observe for leakage
Leakage
Replace
Holding Valve and/or
Seal Kit
Troubleshooting Guide
130
TB 37
SECTION NINE
BOOM ELEVATION SYSTEM DIAGNOSTICS
Inspect
Seals in Cylinder
Remove steel tube on
Cylinder, check if oil is
leaking from upper port
If leaking
Repair or replace
Cylinder
Step 3
Troubleshooting Guide
131
TB 37
SECTION NINE
BOOM ELEVATION SYSTEM DIAGNOSTICS
Boom will not raise
from platform control
(Ground Control Ok)
Inspect
Boom Lift Switch
Check continuity
on wire between
Lift Switch and
Junction Box
If 10 to 12V
Using meter set to
read voltage, measure
voltage on wire #22
Should read 10 to 12 volts
If no reading
Measure voltage on wire
#28 to Lift Switch
Should read 10 to 12 volts
No continuity
If no reading
Repair or replace
Wire #22
Repair or replace
Lift Switch
Step 1
Step 2
Inspect
Lift/Swing Speed
Dial and Valve
Visually check Speed Dial
in platform Control Box for
fast speed.
Dial should be set to fast
If Ok
Replace Dial
If no
voltage
Repair or replace
as needed
If bad
Remove Valve,
visually check to
insure that it is
moving when
power is applied
and that O'Rings
are ok.
Troubleshooting Guide
While activating swing
function, use a meter set to
read voltage, measure
voltage on wire #108B at
Speed Dial.
Should read 10-12 volts
If 10-12V
If 10-12V
While activating Lift
function, measure voltage
on wire #108 at Lift/Swing
Speed Valve.
Should read 10-12 volts
If Ok
If no voltage
Go to step 4
Repair wire to Valve
132
TB 37
SECTION NINE
BOOM ELEVATION SYSTEM DIAGNOSTICS
Boom will not raise
from ground control
Inspect
Boom Lift Switch
Check continuity
on wire between
Lift Switch and Lift
Valve
If 10 to 12V
Using meter set to
read voltage, measure
voltage on wire #22
Should read 10 to 12 volts
If no reading
If 10 to 12V
No continuity
Repair or replace
Wire #22 and retry
function
Measure voltage on wire
#28 to Lift Switch
Should read 10 to 12 volts
If no reading
Repair or replace
Lift Switch
If still no function
Go to step 2
Step 1
Step 2
Inspect
Lift/Swing Speed
Valve
Repair
Switch and/or Wire
If no
voltage
Using a meter set to
read voltage, measure
voltage on wire #108B to
Lift/Swing Speed Valve
Should read 10-12 volts
If 10-12V
Replace Valve
If valve
is stuck
Remove Lift/Swing Speed
Valve from Control Valve,
visually check for proper
operation.
Valve is normally closed
If Ok
Go to step 3
Troubleshooting Guide
133
TB 37
SECTION NINE
BOOM ELEVATION SYSTEM DIAGNOSTICS
Machine function will be
moving when manual
override is activated.
Inspect
Lift Control Valve
Replace
Lift Solenoid
If boom
operates
Activate manual override
on Valve, observe boom
movement
If boom does not move
Install a 5000 psi pressure
gauge on test port,
operate function and
check pressure.
Should read 2500 psi
Repair or replace
Lift Cylinder
Reset Lift/Swing
Relief Valve
If low reading
If boom
operates
If low
reading
Remove hose from #2 Port
of Lift Cylinder, plug hose
and cap cylinder. Recheck
pressure
Step 3
Troubleshooting Guide
134
TB 37
SECTION TEN:
TELESCOPE SYSTEM DIAGNOSTICS
SECTION TEN
TELESCOPE SYSTEM DIAGNOSTICS
Chart 1
Boom will not
retract from
ground control
Step 1
Activate
Manual Override
Step 2
OK
Inspect
Extend and Retract Switch
Step 3
Go to Page
139
Go to Page
139
OK
Inspect
Retract Solenoid
Go to Page
140
Activate
Manual Override
Go to Page
141
Chart 2
Boom will not
retract from
platform control
(Ground Control Ok)
Step 1
Step 2
OK
Inspect
Extend and Retract Switch
Step 3
Go to Page
141
OK
Inspect
Wiring in Hose Carrier
Go to Page
142
Activate
Manual Override
Go to Page
143
Chart 3
Boom will not
extend from
ground control
Step 1
Step 2
OK
Inspect
Extend and Retract Switch
Step 3
OK
Inspect
Extend Solenoid
Step 4
Go to Page
144
OK
Inspect
Extend/Retract Valve
Troubleshooting Guide
Go to Page
143
137
Go to Page
144
TB 37
SECTION TEN
TELESCOPE SYSTEM DIAGNOSTICS
Chart 4
Boom will not
extend from
platform control
(Ground Control Ok)
Step 1
Activate
Manual Override
Step 2
OK
Inspect
Extend and Retract Switch
Step 3
Go to Page
145
Go to Page
145
OK
Inspect
Wiring in Hose Carrier
Go to Page
146
Activate
Holding Valves for Extend
Go to Page
147
Chart 5
Step 1
Boom drifts in
Step 2
OK
Inspect
Cylinder for Internal Leakage
Troubleshooting Guide
138
Go to Page
147
TB 37
SECTION TEN
TELESCOPE SYSTEM DIAGNOSTICS
Boom will not retract
from ground control
Machine function will be
moving when manual
override is activated.
Activate
Manual Override
Go to step 4
If no
movement
Activate Ground Control
Switch, push in on
Manual Override and
observe boom movement
If retracting
Go to step 2
Step 1
Step 2
Inspect
Extend and
Retract Switch
Go to step 3
If
10-12V
Using meter set to read
voltage, measure voltage
at wire #15 at
Extend and Retract
Switch
Should read 10-12 volts
If no reading
Repair or replace
Extend and
Retract Switch
Troubleshooting Guide
139
TB 37
SECTION TEN
TELESCOPE SYSTEM DIAGNOSTICS
Inspect
Retract Solenoid
Replace
Retract Solenoid
If 10-12V
Using meter set to read
voltage, activate function
and measure voltage on
wire #15 to Retract
Solenoid
Should read 10-12 volts
If no reading
Repair or replace
Wire to Valve
Step 3
Step 4
Inspect
Extend/Retract
Valve
Install a 5000 psi pressure
gauge on test port,
operate function and
check pressure.
Should read 1500 psi
If low or no pressure
Repair or replace
Extend Cylinder
and/or Holding
Valve
If
pressure
Ok
Remove hose from Retract
Port of Control Valve, plug
hose and cap valve.
Recheck pressure
If low or no pressure
Adjust 1500 psi Relief in
Control Valve
Troubleshooting Guide
140
TB 37
SECTION TEN
TELESCOPE SYSTEM DIAGNOSTICS
Boom will not retract
from platform control
(Ground Control Ok)
Machine function will be
moving when manual
override is activated.
Activate
Manual Override
Activate Ground Control
Switch, push in on
Manual Override and
observe boom movement
If retracting
Go to step 2
Step 1
Step 2
Inspect
Extend and
Retract Switch
Go to step 3
If
12V
Using meter set to read
voltage, measure voltage
at wire #15 at
Extend and Retract
Switch
Should read 10-12 volts
If no reading
Repair or replace
Extend and
Retract Switch
Troubleshooting Guide
141
TB 37
SECTION TEN
TELESCOPE SYSTEM DIAGNOSTICS
Inspect
Wiring in Hose
Carrier
Using meter set to read
voltage, activate function
and measure voltage at
wire #15 in
Ground Control Box
Should read 10-12 volts
If no reading
Repair or replace
Wiring in Hose Carrier
Step 3
Troubleshooting Guide
142
TB 37
SECTION TEN
TELESCOPE SYSTEM DIAGNOSTICS
Boom will not extend
from ground control
(Platform Control Ok)
Machine function will be
moving when manual
override is activated.
Activate
Manual Override
Activate Ground Control
Switch, push in on
Manual Override and
observe boom movement
If extending
Go to step 2
Step 1
Step 2
Inspect
Extend and
Retract Switch
Go to step 3
If
12V
Using meter set to read
voltage, measure voltage
at wire #14 at
Extend and Retract
Switch
Should read 10-12 volts
If no reading
Repair or replace
Extend and
Retract Switch
Troubleshooting Guide
143
TB 37
SECTION TEN
TELESCOPE SYSTEM DIAGNOSTICS
Inspect
Extend Solenoid
Replace
Extend Solenoid
If 10-12V
Using meter set to read
voltage, activate function
and measure voltage on
wire #14 to Extend
Solenoid
Should read 10-12 volts
If no reading
Repair or replace
Wire to Valve
Step 3
Step 4
Inspect
Extend/Retract
Valve
Install a 5000 psi pressure
gauge on test port,
operate function and
check pressure.
Should read 1500 psi
If low or no pressure
Repair or replace
Extend Cylinder
If
pressure
Ok
Remove hose from Extend
Port of Control Valve, plug
hose and cap valve.
Recheck pressure
If low or no pressure
Adjust 1500 psi Relief in
Control Valve
Troubleshooting Guide
144
TB 37
SECTION TEN
TELESCOPE SYSTEM DIAGNOSTICS
Boom will not extend
from platform control
(Ground Control Ok)
Machine function will be
moving when manual
override is activated.
Activate
Manual Override
Activate Ground Control
Switch, push in on
Manual Override and
observe boom movement
If extending
Go to step 2
Step 1
Step 2
Inspect
Extend and
Retract Switch
Go to step 3
If
12V
Using meter set to read
voltage, measure voltage
at wire #14 at
Extend and Retract
Switch
Should read 10-12 volts
If no reading
Repair or replace
Extend and
Retract Switch
Troubleshooting Guide
145
TB 37
SECTION TEN
TELESCOPE SYSTEM DIAGNOSTICS
Inspect
Wiring in Hose
Carrier
Using meter set to read
voltage, activate function
and measure voltage on
wire #14 in
Ground Control Box
Should read 10-12 volts
If no reading
Repair or replace
Wiring in Hose Carrier
Step 3
Troubleshooting Guide
146
TB 37
SECTION TEN
TELESCOPE SYSTEM DIAGNOSTICS
Boom drifts in
Inspect
Holding Valves for
Extend
Visually check for blown
O-Rings
If Ok
If stuck and/or blown
Go to step 2
Repair or replace
Holding Valves
and/or
O-rings
Step 1
Step 2
Inspect
Seals in Extend
Cylinder
Raise boom and extend
boom 2 ft., remove hoses
from Extend Control Valve.
Observe oil leakage
Leakage
from Port 2
of Extend
Cylinder
Leakage from Port 1
of Extend Cylinder
Repair or replace
Seals in Extend Cylinder
Repair or replace
Holding Valve
Troubleshooting Guide
147
TB 37
SECTION ELEVEN:
FUEL SYSTEM DIAGNOSTICS
SECTION ELEVEN
FUEL SYSTEM DIAGNOSTICS
Chart 1
Engine will not
start on Gasoline,
but will start
on L.P.
Inspect
Fuel Level
Go to Page
152
OK
Inspect
Dual Fuel Switch
Go to Page
152
OK
Inspect
Fuel Shutoff Valve
Go to Page
153
Inspect
L.P. Gauge
Go to Page
154
Chart 2
Engine will not
start on L.P.,
but will start on
Gasoline.
OK
Inspect
Dual Fuel Switch
Go to Page
154
OK
Inspect
L.P. Filter Lock
Troubleshooting Guide
151
Go to Page
155
TB 37
SECTION ELEVEN
FUEL SYSTEM DIAGNOSTICS
Engine will not start
on Gasoline, but will
start on L.P.
Visually check Fuel
Gauge to verify an
adequate amount of fuel
is in tank
Inspect
Fuel Level
If yes
If not
Go to step 2
Fill tank with Gasoline
Inspect
Dual Fuel Switch
Using meter set to read
voltage, measure voltage
1. on wire #77A at the
Dual Fuel Switch
2. on wire #78 coming
out of Dual Fuel Switch
Should read 10-12 volts
Step 1
Step 2
Go to step 3
If
10-12V
If no reading
Repair or replace
Dual Fuel Switch
Troubleshooting Guide
152
TB 37
SECTION ELEVEN
FUEL SYSTEM DIAGNOSTICS
Inspect
Fuel Shutoff
Valve
Repair
wire to Valve
If no
reading
Using meter set to read
voltage, measure voltage
on wire #78 at the
Fuel Shutoff Valve
Should read 10-12 volts
If 10-12V
Repair or replace
Fuel Shutoff Valve
Step 3
Troubleshooting Guide
153
TB 37
SECTION ELEVEN
FUEL SYSTEM DIAGNOSTICS
Engine will not start
on L.P., but will start
on Gasoline.
Inspect
L.P. Gauge
Visually check
L.P. Gauge to verify an
adequate amount of
fuel is in tank
If yes
If not
Go to step 2
Fill tank with L.P.
Inspect
Dual Fuel Switch
Using meter set to read
voltage, measure voltage
1. on wire #77A at the
Dual Fuel Switch
2. on wire #77B coming
out of Dual Fuel Switch
Should read 10-12 volts
Step 1
Step 2
Go to step 3
If
10-12V
If no reading
Repair or replace
Dual Fuel Switch
Troubleshooting Guide
154
TB 37
SECTION ELEVEN
FUEL SYSTEM DIAGNOSTICS
Inspect
L.P. Filter Lock
Repair
wire to Valve
If no
reading
Using meter set to read
voltage, measure voltage
1. on wire #77B at the
L.P. Filter Lock
2. on wire #78 coming
out of Dual Fuel Switch
Should read 10-12 volts
If 10-12V
Repair or replace
L.P. Filter Lock
Step 3
Troubleshooting Guide
155
TB 37
SECTION TWELVE:
ACCESSORIES DIAGNOSTICS
SECTION TWELVE
ACCESSORIES DIAGNOSTICS
Chart 1
Step 1
AC Generator
will not function
Inspect
Power to Generator Switch
at Platform
Step 2
Go to Page
160
OK
Inspect
Generator Solenoid
Go to Page
160
Inspect
AC Voltage from Generator
Go to Page
161
Chart 2
Step 1
AC Generator has
low voltage
Chart 3
Step 1
Machine will not
steer
Troubleshooting Guide
Inspect
Tow Package Float Valve
159
Go to Page
162
TB 37
SECTION TWELVE
ACCESSORIES DIAGNOSTICS
AC Generator will
not function
Using meter set to read
voltage, measure voltage
at wire #169 when
switch is activated to
Generator position
Should read 10-12 volts
Inspect
Power to
Generator Switch
at Platform
If
10-12V
If no reading
Repair or replace
Generator Switch at
Platform
Go to step 2
Step 1
Step 2
Inspect
Generator
Solenoid
If
10-12V
Repair or replace
Solenoid Valve
Troubleshooting Guide
160
Using meter set to read
voltage, measure voltage
on Generator Solenoid
wire #169
Should read 10-12 volts
If no reading
Repair or replace
Wire from Platform
TB 37
SECTION TWELVE
ACCESSORIES DIAGNOSTICS
AC Generator has
low voltage
Inspect
AC Voltage from
Generator
Using meter set to read
voltage, measure voltage
at Generator
Should read 130 volts AC
If no reading
Adjust Speed Control
Valve on Hydraulic
Generator Valve
counterclockwise to
increase voltage
Step 1
Troubleshooting Guide
161
TB 37
SECTION TWELVE
ACCESSORIES DIAGNOSTICS
Machine will
not steer
Inspect
Tow Package
Float Valve
Visually inspect Tow
Package Float Valve
to insure valve is in
operational position
No
Check decal for correct
positioning
Step 1
Troubleshooting Guide
162
TB 37