Wiper/Washer System Description and Operation
Wiper/Washer System Components
The Wiper/Washer System consists of the following components:
•
Windshield wiper/washer switch
•
Body control module (BCM)
•
Wiper HI/LO relay
•
Wiper ON/OFF relay
•
Wiper RUN/ACC relay
•
Wiper diode
•
Windshield wiper motor
•
Windshield washer pump
•
WIPER fuse 30A
•
WPR/WASHER fuse 10A
•
WIPER DWELL fuse 10A
Windshield Wiper/Washer System Power and Ground
With the ignition in the ON position, accessory voltage is supplied through the 30A WIPER fuse to the wiper ON/OFF relay and the
wiper RUN/ACC relay that are all located in the underhood fuse block. With the wiper RUN/ACC relay energized, accessory voltage
is supplied to the WPR/WASHER 10A fuse that is located in the instrument panel (I/P) fuse block. Refer to Wiper/Washer
Schematics.
G201 provides ground for the windshield wiper motor. G101 provides ground for the following components:
•
Windshield washer fluid pump
•
Windshield washer fluid level switch
•
Headlamp washer fluid pump
Wiper/Washer System Description
The windshield wiper motor is a 2-speed motor and is operated at LOW speed in all wiper modes except for HIGH. With the ignition
in the ON position, accessory voltage is supplied to the windshield wiper/washer switch from the WPR/WASHER fuse located in the
instrument panel (I/P) fuse block. The body control module (BCM) controls all wiper motor mist, wash, delay and low speed
operations based on inputs received from the wiper/washer switch. The washer pump and high wiper operations are controlled directly
by the wiper/washer switch.
Low Speed Operation
When the wiper switch is in the low speed position, battery positive voltage is applied through the switch internal resistor and the
wiper switch low signal circuit to the body control module (BCM). In response to this signal, the BCM energizes the wiper ON/OFF
relay by applying battery voltage through the windshield wiper switch signal 2 circuit to the coil side of the relay. This allows battery
positive voltage from the WIPER fuse to flow through the input side of the ON/OFF relay and out to the switch side of the HI/LO
relay. Since the wiper HI/LO relay is de-energized and its switch contacts are normally closed to the low speed control circuit of the
windshield wiper motor, the motor will operate at low speed.
Wiper motor low speed operation and the wiper ON/OFF relay can also be commanded ON/OFF by using a scan tool.
Mist Operation
Windshield wiper/washer system mist operation is identical to low operation, except that the mist switch is a press and release type
switch. When the wiper switch is moved to the mist position and released, low speed wiper motor operation is started and will
continue until 1 wipe cycle is complete. If the wiper switch is moved to the mist position and held, the wiper motor will operate in the
low mode until the switch is released.
Intermittent Operation
Windshield wiper delay operation is a low speed wiper motor function with a variable delay interval between the wiper motor cycles.
The delay interval is determined by a series of 5 resistors within the wiper/washer switch. The body control module (BCM) monitors
the voltage on the wiper switch low signal circuit to determine the delay interval between the low speed wiper motor cycles.
If the wiper switch is moved from one delay interval to another, the BCM will command an immediate wipe cycle, and reset the delay
timer.
Wash Operation
When the windshield Wash switch is pressed, battery voltage is applied through the switch contacts and the windshield washer switch
signal circuit and the body control module (BCM) to the windshield washer pump. The BCM monitors the voltage on the windshield
washer switch signal circuit to detect when a WASH cycle is requested so it can also enable the wipers. After a short delay, the BCM
energizes the wiper ON/OFF relay which will operate the windshield wiper motor at low speed. The wiper motor will continue to
operate for 2 wipe cycles after the wash switch is released.
High Speed Operation
When the wiper switch is in the high speed position, battery voltage is applied through the windshield wiper switch high signal circuit
to both the wiper ON/OFF relay and wiper HI/LO relay coils. This energizes both relays and allows battery voltage from the WIPER
fuse to flow through the wiper ON/OFF relay to the switch input of the wiper HI/LO relay through its switch contacts and out to the
high speed control circuit of the wiper motor.
Park Position Operation
Windshield wiper motor park operation is controlled by the body control module (BCM) using an input from the park switch that is
located within the wiper motor assembly. The BCM monitors the windshield wiper motor park switch signal circuit, which includes
the 10 A WIPER DWELL fuse, to determine if the windshield wiper blades are at the bottom of the glass. During wiper operation,
each time the wiper blades are at the bottom of the glass, the park switch is momentarily closed to ground signaling the BCM the
wiper position. When the wiper switch is turned to the OFF position while the wiper motor is somewhere in mid-cycle, the BCM will
continue to operate the motor until the wipers reach the park position. If the ignition is turned OFF while the wipers are in mid-cycle,
the wipers will stop immediately where they are. The BCM will park the wipers the next time the ignition is turned ON.
The wipers will not park when they are commanded ON and OFF with a scan tool. The BCM will park the wipers the next time the
wiper switch is turned ON and OFF.
Diagnostic Instructions
• Perform the Diagnostic System Check - Vehicle prior to using the diagnostic procedure.
• Review Strategy Based Diagnosis for an overview of the diagnostic approach.
• Diagnostic Procedure Instructions provides an overview of each diagnostic category.
Diagnostic Fault Information
Short to
Circuit
Ground
WIPER 2 Relay B+
1, 2
Windshield Wiper Switch Signal.
B3922 00
Windshield Wiper Switch High Signal 4
Windshield Wiper Motor Park Switch
3
Signal
WIPER 1 Relay Control
B3715 00
WIPER 2 Relay Control
4
Windshield Wiper Motor High Speed
2
Control
Windshield Wiper Motor Low Speed
1
Control.
Windshield Wiper Switch Low
-Reference
Windshield Wiper Motor Ground
-WIPER 1 Relay Ground
-1. Delay or low speed wipers inoperative
2. High speed wipers inoperative
3. Wipers do not park
4. Wipers always on
Open/High
Resistance
1, 2
1
2
Short to
Voltage
-1
2
Signal
Performance
----
3
--
--
1
2
4
B3875 00
---
2
4
--
1
4
--
1, 2
1, 2, 3
1
1
2
---
----
Circuit/System Description
Wiper Mist, Delay 1-5, and Low are all low speed wiper motor functions that are controlled by the body control module (BCM).
When the wiper switch is placed in one of the LOW speed wiper modes, ground is applied through the switch contacts a series of
internal resistors and the wiper switch low signal circuit to the BCM. In response to this signal, the BCM energizes the WPR Relay by
applying battery voltage through the wiper relay control circuit to the coil side of the relay. This allows battery positive voltage from
the WPR fuse to flow through the switch input side of the WPR Relay and out to the switch input side of the WIPER HI Relay. Since
the wiper high relay is de-energized and its switch contacts are normally closed to the low speed control circuit of the windshield
wiper motor, the motor will operate at low speed.
When the wiper switch is placed in the HIGH speed position, ground is applied through the switch contacts and the wiper switch high
signal circuit to the BCM indicating the wiper high speed request. The BCM then energizes WPR Relay as stated above and the
WIPER HI Relay by applying ground through the control circuit to the coil side of the relay. With the wiper high relay energized and
its switch contacts closed to the high speed control circuit of the wiper motor, the motor will operate at high speed.
Diagnostic Aids
• A short to ground in the following circuits will open the WPR fuse:
Ignition 1 voltage
Windshield wiper motor relay coil supply voltage
Windshield wiper switch high signal
Windshield wiper motor low speed control
Windshield wiper motor high speed control
• A short to B+ on any of the wiper/washer switch signal circuits will open the ground trace in the wiper switch.
Reference Information
Schematic Reference
Wiper/Washer Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Wiper/Washer System Description and Operation
Electrical Information Reference
•
Circuit Testing
•
Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
•
Wiring Repairs
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
BCM and Wiper Switch Verification
1. Ignition ON, observe the scan tool Windshield Wiper Switch and the Wiper Delay Setting parameters. The Windshield Wiper
Switch reading should display Off, Intermittent and Low and the Wiper Delay Setting should display 0-5 while rotating the
wiper switch through each delay setting to the low position.
⇒If one or more of the Wiper Delay Setting parameters are inoperative and the Windshield Wiper Switch low speed
parameter functions, replace the turn signal/multifunction switch.
⇒If the low speed parameter is inoperative, perform the Multifunction Switch Circuit/System Testing and/or the
Multifunction Switch Component Test.
2. With the wiper switch in the HIGH speed mode, observe the scan tool Wiper High Speed Switch parameter. The Wiper High
Speed Switch reading should be Active.
⇒If not Active, perform the Multifunction Switch Circuit/System Testing and/or the Multifunction Switch
Component Test.
3. Observe the scan tool BCM Wiper Park Switch parameter. The reading should display Active when the wipers are parked
and Inactive with the wipers ON or out of the park position.
⇒If the Wiper Park Switch parameter is always Active or Inactive, perform the Wipers do not Park Circuit/System
Testing.
4. If all wiper position parameters displayed correctly on the scan tool, perform the Wiper Motor Circuit/System Testing and/or
the Wiper Motor Component Test.
BCM and Wiper Motor Verification
1. Command the windshield wiper motor to the off, low speed and high speed modes with a scan tool. Before commanding the
wiper high speed mode, place the wiper switch in the low speed position. The wipers should perform the commanded state.
⇒If one or more of the commanded states do not work, perform the Wiper Motor tests in Circuit/System Testing
and/or Component test.
2. If all the wiper motor speeds function, perform the Multifunction Switch Circuit/System Testing and/or the Multifunction
Switch Component Test.
Circuit/System Testing
Multifunction Switch Circuit/System Testing
1. Ignition OFF, disconnect the X1 harness connector at the turn signal/multifunction switch.
2. Ignition OFF, test for less than 20.0 ohms between the ground circuit terminal H and ground.
⇒If greater than 20.0 ohms check the ground circuit for an open/high resistance. If the circuit tests normal replace
the BCM.
3. Verify the scan tool Windshield Wiper High Speed Switch parameter is Inactive.
⇒If not the specified value, test the signal circuit terminal L for a short to ground. If the circuit tests normal, replace
the BCM.
4. Verify the scan tool Wiper High Speed Switch parameter is Inactive.
⇒If not Inactive, test the signal circuit terminal K for a short to ground. If the circuit tests normal, test or replace the
BCM.
5. Install a 3A fused jumper wire between the signal circuit terminal L and ground. Verify the scan tool Windshield Wiper
Switch parameter is Switch Fault.
⇒If not Switch Fault, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests
normal, test or replace the BCM.
6. Install a 3A fused jumper wire between the signal circuit terminal K and ground. Verify the scan tool Wiper High Speed
Switch parameter is Active.
⇒If not Active, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, test
or replace the BCM
7. If all circuits test normal, test or replace the turn signal/multifunction switch.
Wipers Do Not Park Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the windshield wiper motor.
2. Ignition ON, verify the scan tool BCM Wiper Park Switch parameter is Inactive.
⇒If not Inactive, test the signal circuit terminal C for a short to ground. If the circuit tests normal, test or replace the
body control module.
3. Install a 3A fused jumper wire between the wiper motor park switch signal circuit terminal C and ground. Verify the scan
tool Wiper Park Switch parameter is Active.
⇒If not Active, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the body control
module.
4. If all circuits test normal, test or replace the windshield wiper motor.
WIPER 1 Relay Control Test
1. Ignition OFF, disconnect the X5 harness connector at the BCM
2. Ignition ON, verify that the low speed wipers are not on.
⇒If the low speed wipers are on, test the relay control circuit terminal 20 for a short to voltage. If the circuit tests
normal, Replace the underhood fuse block.
3. Install a 10A fused jumper wire between the relay control circuit terminal 20 and B+. Verify the low speed wipers are on.
⇒If the low speed wipers are not on, test the relay control circuit for an open/high resistance or short to ground. If
the circuit tests normal, replace the underhood fuse block
4. If all circuits test normal, replace the BCM.
WIPER 2 Relay Control Circuit Test
1. Ignition OFF, disconnect the X5 harness connector at the BCM
2. Install a 10A fused jumper wire between B+ and WIPER 1 relay control circuit terminal 20.
3. Ignition ON, verify that the high speed wipers are not on.
⇒If the high speed wipers are on, test the WIPER 2 control circuit terminal 21 for a short to ground. If the circuit
tests normal, replace the underhood fuse block.
4. Install a 10A fused jumper wire between the WIPER 2 relay control circuit terminal 21 and ground. Verify the high speed
wipers are on.
⇒If the high speed wipers are not on, test the relay control circuit for an open/high resistance or short to voltage. If
the circuit tests normal, replace the underhood fuse block.
5. If all circuits test normal, replace the BCM.
Wiper Motor Circuit Test
1. Disconnect the harness connector at the windshield wiper motor.
2. Test for less than 1 ohm between the wiper motor ground circuit terminal 5 and ground.
⇒If greater than the specified range, test the ground circuit for an open/high resistance.
3. Connect a test lamp between the low speed motor control circuit terminal 1 and ground.
4. Ignition ON, command the Wiper Relay ON and OFF with a scan tool. The test lamp should turn ON and OFF when
changing between the commanded states.
⇒If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the
underhood fuse block.
⇒If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit
tests normal, replace the underhood fuse block.
5. Connect a test lamp between the high speed motor control circuit terminal 4 and ground.
6. Wiper switch in the Low position , command the wiper high speed relay ON and OFF with a scan tool. The test lamp should
turn ON and OFF when changing between the commanded states
⇒If the test lamp is always on, test the control circuit for a short to voltage, if the circuit tests normal, replace the
underhood fuse block.
⇒If the test lamp is always OFF, test the control circuit for a short to ground or open/high resistance. If the circuit
tests normal, replace the underhood fuse block.
7. If all circuits test normal, replace the windshield wiper motor.
Component Testing
Multifunction Switch
1. With the ignition OFF, disconnect the X1 harness connector at the turn signal/multifunction switch.
2. Test the resistance between terminals H and L. Rotate the wiper switch and compare the resistance readings to the values in
the Windshield Wiper Switch Values table below for MIST, each DELAY and LOW speed.
⇒If the resistance is not within the specified range, replace the turn signal/multifunction switch.
3. Test for infinite resistance between terminals H and K while rotating the wiper switch to MIST, each DELAY and LOW
speed positions.
⇒If the less than infinite, replace the turn signal/multifunction switch.
4. Test for less than 5 ohms with the wiper switch in the High speed position.
⇒If greater than 5 ohms, replace the turn signal/multifunction switch.
5. Test for infinite resistance between terminals H and J while rotating the wiper switch to MIST, each DELAY and LOW
speed positions.
⇒If less than infinite, replace the turn signal/multifunction switch.
6. Test for less than 5 ohms while pressing the WASHER switch.
⇒If greater than 5 ohms, replace the turn signal/multifunction switch.
Important: If the switch tests open in any switch position other than Off, test the wiper/washer switch signal circuits for a short to
voltage before replacing the switch.
Wiper Switch Values
Switch Position
Resistance
Off
Infinite
Mist
300-364 Ω
Delay 1
3.48k-4.25k Ω
Delay 2
2.52k-3.08k Ω
Delay 3
1.78k-2.18k Ω
Delay 4
1.17k-1.44k Ω
Delay 5
697-851 Ω
Low
300-364 Ω
Windshield Wiper Motor Dynamic Test
1. Ignition OFF, disconnect the harness connector at the windshield wiper motor.
2. Install a 25A fused jumper wire between the control terminal B and 12 volts. Install a jumper wire between the ground
terminal A and ground.
3. The wiper motor should be in low speed mode.
⇒If the wiper motor is not in the low speed mode replace the motor.
4. Install a 25A fused jumper wire between the control terminal A and 12 volts. Install a jumper wire between the ground
terminal D and ground.
5. The wiper motor should be in the high speed mode.
⇒If the wiper motor is not in the high speed mode replace the motor.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
•
Turn Signal Multifunction Switch Replacement
•
Windshield Wiper Motor Replacement
• Underhood Electrical Center or Junction Block Replacement
• Control Module References for BCM replacement, setup, and programming
DTC B3715
Diagnostic Instructions
• Perform the Diagnostic System Check - Vehicle prior to using the diagnostic procedure.
• Review Strategy Based Diagnosis for an overview of the diagnostic approach.
• Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptor
DTC B3715 02: Front Wiper Relay Drive Circuit Short to Ground
DTC B3715 05: Front Wiper Relay Drive Circuit Short to Battery or Open
Diagnostic Fault Information
Circuit
Windshield Washer Switch Signal
Short to
Ground
6
8
Windshield Wiper Motor Relay Coil
B3715 02
Supply Voltage
Windshield Wiper Switch High Signal
6
Windshield Wiper Switch Low Signal
-Windshield Wiper Motor Park Switch
5
Signal
Windshield Wiper Motor High Speed
2
Control
Windshield Wiper Motor Low Speed
2
Control
Windshield Wiper Motor Ground
-Windshield Wiper Switch Ground
-Wiper High Speed Relay Control
7
Wiper Relay Ground
-1. Wipers and washers inoperative all modes
2. Wipers inoperative all modes and washers work
3. Delay or low speed wipers inoperative
4. High speed wipers inoperative
5. Wipers do not park
6. Wipers always on
7. Wipers operate at high speed in the low speed mode
8. Washer malfunction
Open/High
Resistance
Short to
Voltage
Signal
Performance
8
1
--
B3715 05
B3715 05
--
4
3
1
1
---
5
--
--
4
--
--
3
--
--
2
1
4
2
-----
-----
Circuit/System Description
The body control module (BCM) monitors the windshield wiper switch signal 2 circuit that controls wiper ON/OFF relay. The voltage
level on this circuit should be low while the wiper system is off and the relay is de-energized. The voltage will be near system voltage
when the relay is energized. After the BCM receives a low, intermittent, or mist signal from the wiper/washer switch, it responds by
applying battery voltage to the wiper switch signal 2 circuit energizing the wiper ON/OFF relay.
Conditions for Running the DTC
The BCM output is actively being requested.
Conditions for Setting the DTC
B3715 02 The BCM detects a short to ground in the windshield wiper switch signal 2 circuit.
B3715 05 The BCM detects a short to battery or an open in the windshield wiper switch signal 2 circuit.
Action Taken When the DTC Sets
The BCM will not activate the output.
Conditions for Clearing the DTC
• The current DTC will become history when the request for the output is removed or when the condition for
setting the fault is corrected.
• The history DTC will clear after 50 consecutive ignition cycles without a fault present.
Reference Information
Schematic Reference
Wiper/Washer Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Wiper/Washer System Description and Operation
Electrical Information Reference
•
Circuit Testing
•
Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
•
Wiring Repairs
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Testing
1. Ignition OFF, disconnect the WPR ON/OFF relay.
2. Connect a test lamp between the control circuit terminal K11 and ground.
3. Ignition ON, command the low speed wipers ON and OFF using the wiper switch. The test lamp should turn ON and OFF
when changing between the commanded states.
⇒If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the
BCM.
⇒If the test lamp is always OFF, test for a short to ground or an open/high resistance on the control circuit. If the
circuit tests normal, replace the BCM.
4. If all circuits test normal, test or replace the WPR ON/OFF relay.
Component Testing
Ignition OFF, disconnect the WPR ON/OFF relay.
5. Test for 60-200 ohms between terminals 85 and 86.
⇒If the resistance is not within the specified range, replace the relay.
6. Test for infinite resistance between the following terminals:
•
30 and 86
•
30 and 87
•
30 and 85
•
85 and 87
⇒ If not the specified value, replace the relay.
7. Test for less than 2 ohms between terminals 30 and 87A.
⇒ If greater than the specified range, replace the relay.
8. Install a 10A fused jumper wire between relay terminal 85 and 12 volts. Install a jumper wire between relay terminal 86 and
ground. Test for less than 2 ohms between terminals 30 and 87.
⇒ If greater than the specified range, replace the WSW relay.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
•
Relay Replacement
• Underhood Electrical Center or Junction Block Replacement
• Control Module References for BCM replacement, setup, and programming