54.26
Wiper/Washer System
General Information
Description
Wiper Motor
The instrumentation control unit (ICU) monitors wiper
control dial and washer switch position information
from the multifunction turn signal switch and sends this
information via J1939 messages to the Bulkhead Module (BHM). The BHM takes these messages from the
ICU and uses the information to control the windshield
wiper motor and the washer pump motor.
The wiper motor is a two-speed motor that runs the
wipers at low speed or high speed. For the five
intermittent positions, the wipers are pulsed at low
speed. There is a short time delay between pulses
that varies in duration according to the position of the
wiper control dial.
The BHM controls the wiper motor speed by monitoring three J1939 messages that are received from the
ICU. The three messages are:
Wiper Control Dial
The wiper control dial at the end of the multifunction
turn signal switch controls the operation of the wiper.
See Fig. 1. There are two steady-speed settings, LO
and HI, and five delay settings. The delay settings
are indicated by five lines of various lengths on the
wiper control dial. The longer the length of the line,
the shorter the delay between wipes.
Rotate the wiper control dial away from you to turn
the wipers on. When the wipers are on, rotate the
wiper control dial toward you to turn the wipers off.
See Fig. 2.
See Specifications 400 for wiper control dial input/
output signals sent to the ICU.
• wiper on/off message
• wiper low message
• wiper high message
When one of the intermittent speeds is selected, the
ICU controls the timing of the wipers by pulsing the
wiper on/off and wiper low messages. See Specifications 400 for the I/O conditions of the wiper motor
operation.
The BHM also monitors the wiper motor wiring and
is capable of detecting a short circuit. Faults discovered by the BHM may be reported on the J1939
and/or J1708 datalinks and can be viewed through
ServiceLink®. See Troubleshooting 300 for possible
wiper motor fault conditions.
4
5
2
1
3
1
2
3
4
5
11/16/2001
1.
2.
3.
4.
5.
f820386
Washer Button
Wiper Control Dial
Turn Signal Lever
Hazard Flasher
Multifunction Turn Signal Switch Module
Fig. 1, Multifunction Turn Signal Switch
f820383
10/29/2001
1.
2.
3.
4.
5.
Washer Button
Wiper Off Position
Wiper Delay Positions
Low-speed Wiper Position
High-speed Wiper Position
Fig. 2, Wiper/Washer Controls
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050/1
54.26
Wiper/Washer System
General Information
Washer Pump
Washer Fluid Level
The washer pump is operated by a button at the end
of the multifunction turn signal switch. To operate the
washer, press the button in and hold it in for the length
of wash you want. See Table 1 for a description of the
available wash cycles. Unless the wiper control dial
is in the high position, wiping triggered by the wash
button is done at low speed.
If the vehicle is equipped with an optional washer
fluid level switch, the BHM will monitor the level of
the washer fluid in the fluid reservoir and send this
information to the ICU via a J1939 message. When
the BHM sees ground at the washer fluid level input,
it sends a J1939 message to the ICU indicating
low washer fluid. The ICU then illuminates the low
washer fluid indicator. If the washer fluid level input
is unavailable or in error, the BHM will assume the
washer fluid level is low.
The BHM monitors the washer pump motor wiring
and is capable of detecting a short circuit. Faults
discovered by the BHM may be reported on the J1939
and/or J1708 datalinks and can be viewed through
ServiceLink. See Troubleshooting 300 for possible
washer pump fault conditions.
Washer Cycles
Cycle Activation Requirements
Cycle Description
Wash button is pressed less than 0.5 second.
Single dry wipe, commonly called a mist wipe.
Wash button is pressed from 0.5 to 1.0 second.
Short wash with three wipes.
Wash button is pressed more than 1.0 second.
Wash continues until the button is released.
Table 1, Washer Cycles
050/2
Business Class M2 Workshop Manual, Supplement 10, September 2006
54.26
Wiper/Washer System
Troubleshooting
Fault Codes
Wiper Motor
The reference parameters that program the Bulkhead
Module (BHM) determine whether a fault code will
broadcast for any wiper/washer system fault. Even
if the BHM detects a wiper/washer system fault, a
fault code may not be transmitted. If the BHM is
programmed to transmit wiper/washer system fault
codes, they can be viewed through ServiceLink®. Fault
messages may be transmitted on the J1939 datalink,
the J1708 datalink, or both.
Table 2 displays how the BHM handles wiper motor
faults.
Washer Pump
Table 3 displays how the BHM handles washer pump
faults.
Wiper Control Dial
Table 1 displays wiper control dial message combinations that create a fault.
Wiper Control Dial Fault Conditions
J1939 Wiper Control Dial Messages
Action Taken by the BHM
Wiper On/Off
Wiper Low
Wiper High
Off
On
Off
BHM may transmit a J1939 and/or a J1708 fault message.
On
Off
Off
BHM may transmit a J1939 and/or a J1708 fault message.
On
On
On
BHM may transmit a J1939 and/or a J1708 fault message.
Off
On
On
BHM may transmit a J1939 and/or a J1708 fault message.
Off
Off
On
BHM may transmit a J1939 and/or a J1708 fault message.
Table 1, Wiper Control Dial Fault Conditions
Wiper Motor Fault Conditions
Description of Fault
Action Taken by the BHM
Ignition switch is in error.
BHM will assume the ignition switch is on, and may transmit
a fault message on the J1939 and/or J1708 datalinks.
Wiper commutator switch is unavailable or in error.
BHM will assume the wiper commutator switch is in the park
position.
J1939 wiper on/off message from the instrumentation control
BHM may transmit a J1939 and/or a J1708 fault message.
unit (ICU) is unavailable or in error.
J1939 wiper low message from the ICU is unavailable or in
error.
BHM may transmit a J1939 and/or a J1708 fault message.
J1939 wiper high message from the ICU is unavailable or in
error.
BHM may transmit a J1939 and/or a J1708 fault message.
Contradictory J1939 messaging between the ICU and BHM.
BHM may transmit a J1939 and/or a J1708 fault message.
ICU sends an error indicator in any of the J1939 wiper
messages to the BHM.
BHM may transmit a J1939 and/or a J1708 fault message.
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300/1
54.26
Wiper/Washer System
Troubleshooting
Wiper Motor Fault Conditions
Description of Fault
Action Taken by the BHM
BHM fails to receive any five consecutive J1939 wiper
messages from the ICU.
BHM may transmit a J1939 and/or a J1708 fault message.
Short in the wiper motor wiring.
BHM may transmit a J1939 and/or a J1708 fault message.
Table 2, Wiper Motor Fault Conditions
Washer Pump Fault Conditions
Description of Fault
Action Taken by the BHM
J1939 washer pump message from the ICU is unavailable
or in error.
BHM assumes the J1939 washer pump message is off.
ICU sends an error indicator in the J1939 washer pump
message to the BHM.
BHM may transmit a J1939 and/or a J1708 fault message.
BHM fails to receive five consecutive J1939 washer pump
messages from the ICU.
BHM may transmit a J1939 and/or a J1708 fault message.
Short in the washer pump motor wiring.
BHM may transmit a J1939 and/or a J1708 fault message.
Table 3, Washer Pump Fault Conditions
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Business Class M2 Workshop Manual, Supplement 10, September 2006
54.26
Wiper/Washer System
Specifications
Description
The instrumentation control unit (ICU) monitors
windshield wiper control dial and washer switch
position information from the multifunction turn signal
switch and sends this information via J1939 messages
to the Bulkhead Module (BHM). The BHM takes these
messages from the ICU and uses the information to
control the windshield wiper motor and the washer
pump motor. See Fig. 1 for a diagram of the major
components used in the operation of the wiper/washer
system.
Input and Output Conditions
motor speed by monitoring three J1939 messages that
it receives from the ICU. The three messages are:
• wiper on/off message
• wiper low message
• wiper high message
When one of the intermittent speeds is selected at the
multifunction turn signal switch, the ICU controls the
timing of the wipers by pulsing the J1939 wiper on/off
and the J1939 wiper low messages.
Table 1 displays the wiper control dial inputs to the
ICU and the J1939 message outputs.
The wiper motor has a low speed, a high speed, and
five intermittent speeds. The BHM controls the wiper
2
3
4
5
J1939
1
BHM
6
J1708
7
LO
HI
PARK
8
03/02/2006
1.
2.
3.
4.
f040562a
5.
6.
7.
8.
Washer Switch
Wiper Control Dial
Multifunction Turn Signal Switch
Instrumentation Control Unit
Bulkhead Module
Washer Fluid Level Sensor
Washer Pump
Wiper Motor
Fig. 1, Wiper/Washer System
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400/1
54.26
Wiper/Washer System
Specifications
Wiper Control Dial Input/Output Conditions
Inputs to ICU
Wiper Control Dial
Position
Outputs from ICU
Wiper Operation Timing
J1939 Wiper On/Off
Message
J1939 Wiper Low
Message
J1939 Wiper High
Message
OFF
Wiper off
Off
Off
Off
Intermittent 1
Wipe every 17 seconds
Pulsed on
Pulsed on
Off
Intermittent 2
Wipe every 12 seconds
Pulsed on
Pulsed on
Off
Intermittent 3
Wipe every 8 seconds
Pulsed on
Pulsed on
Off
Intermittent 4
Wipe every 5 seconds
Pulsed on
Pulsed on
Off
Intermittent 5
Wipe every 3 seconds
Pulsed on
Pulsed on
Off
LO
Wiper low speed
On
On
Off
HI
Wiper high speed
On
Off
On
Table 1, Wiper Control Dial Input/Output Conditions
Table 2 displays the wiper motor inputs to the BHM
and how the BHM reacts to these inputs.
Wiper Motor Input/Output Conditions
Inputs to BHM
Output from BHM
Ignition Switch
Position
J1939 Wiper On/Off
Message
J1939 Wiper Low
Message
J1939 Wiper High
Message
Wiper Motor Speed
Start/Off
On/Off
On/Off
On/Off
Off
On/Acc
Off
Off
Off
Off
On/Acc
On
On
Off
Low
On/Acc
Off
On
Off
Low*
On/Acc
On
Off
Off
Low*
On/Acc
On
Off
On
High
On/Acc
On
On
On
High*
On/Acc
Off
On
On
High*
On/Acc
Off
Off
On
High*
* This is an error condition. See Specifications 300, for more information concerning fault conditions.
Table 2, Wiper Motor Input/Output Conditions
Wiring Diagram
Fig. 2 shows a wiring diagram
Business Class® M2 wiper/washer
pin identification and circuit colors
diagram may not be representative of
400/2
for a typical
system. BHM
shown on this
every vehicle.
Business Class M2 Workshop Manual, Supplement 10, September 2006
54.26
Wiper/Washer System
Specifications
Cruise
Control
Instrumentation
Control Unit (ICU)
Wiper high speed
Wiper parked
D9 DKG 1939−
C2
B
Y
1939+
473C
6
T
Data
Lines
J DKG 1939−
B2
G
DKBL 320
H
DKBL 316
F
DKBL 318
C DKBL 317
B3
Wiper
Switch
Turn Signal
Multifunction
Switch
L DKBL 320A
B4
F
Bulkhead
Module (BHM)
1939+
PARK
DKBL 320A
Wiper low speed
D5 Y
High speed
Low speed
Intermittent 5
Intermittent 4
Intermittent 3
Intermittent 2
Intermittent 1
Off
2
Washer pump
473C
Wash
Switch
5
T
Wiper
Motor
HIGH
Washer
Pump
Motor
1
2
BK
GND
BK
GND
BK A
LOW
Left Exterior
Frontwall
Ground
03/01/2006
Washer Fluid
Level Switch
(if equipped)
BK−W GNDBK−W
Washer level (spare)
A2 T
C1
473B
DKBL 320
Can low
1
T
1
Can high
473B
DKBL 316
Can low
B7 T
C
Can high
473
DKBL 318
Wiper input
473
B
Washer input
T
Wash norm state
B5 T
DKBL 317
Stalk switch common
473
Battery
Ground
f544771
Fig. 2, Wiper/Washer Wiring Diagram
Business Class M2 Workshop Manual, Supplement 10, September 2006
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