Wipers and Washers

Special Tool(s)

	Flex Probe Kit 105-R025D or equivalent
	Fluke 77-IV Digital Multimeter FLU77-4 or equivalent
	Vehicle Communication Module (VCM) and Integrated Diagnostic System (IDS) software with appropriate hardware, or equivalent scan tool

Principles of Operation

When the ignition switch is in the RUN or ACCESSORY position, voltage is supplied to the wiper relay coil at the Battery Junction Box (BJB). The wiper relay coil is grounded at all times. Voltage is supplied to the wiper relay switch from BJB fuse 9. When the wiper relay is activated, voltage is supplied to the wiper motor.

Wiper Activated Headlamps (if equipped with Autolamp System)

NOTE: The Smart Junction Box (SJB) may also be identified as the Generic Electronic Module (GEM).

The SJB sends a voltage signal to the wiper motor in order to monitor the status of the wipers. When the headlamp control switch is in the AUTOLAMP position and the wipers on, the SJB will activate the headlamps within 10 seconds. When the SJB detects that the wipers have been turned off, the SJB will turn off the headlamps after 30 seconds.

High-Speed Windshield Wipers

When the multifunction switch is set to the HIGH-speed position, it supplies ground to the internal high/low-speed relay coil and the internal run/park relay coil, which causes the windshield wiper motor to operate at high speed. During HIGH-speed operation only, both the internal high/low-speed relay coil ground and the internal run/park relay coil ground are controlled directly by the multifunction switch. This differs from LOW-speed or INTERMITTENT operation when the internal run/park relay coil is controlled by the microprocessor. When the switch is placed in the OFF position, the motor continues to operate until the motor returns to the PARK position and the internal Hall-effect sensor senses the motor magnet. The output to the internal run/park relay then deactivates the relay and disconnects the voltage to the motor.

Since the internal high/low relay coil and the internal run/park relay coil are both controlled by a hard-wired circuit to the multifunction switch, the windshield wipers will still operate in HIGH-speed mode if the internal windshield wiper module fails, but will not automatically park when the multifunction switch is turned to the OFF position.

Low-Speed Windshield Wipers

When the multifunction switch is set to the LOW-speed position, it supplies ground to the internal windshield wiper motor module low-speed input and the windshield wiper motor operates at low speed. During LOW-speed operation, the internal run/park relay is activated by the microprocessor and supplies 12 volts to the low-speed brush of the windshield wiper motor. The internal run/park relay coil ground is controlled by the internal windshield wiper motor module based on inputs received from the multifunction switch. When the switch is placed in the OFF position, the motor continues to operate until the motor returns to the PARK position and the internal Hall-effect sensor senses the motor magnet. The output to the internal run/park relay then deactivates the relay and disconnects the voltage to the motor.

Intermittent-Speed Windshield Wipers

When the multifunction switch is set to the INTERMITTENT position(s), it supplies ground to the windshield wiper motor module inputs and the windshield wiper motor operates in intermittent mode. During intermittent operation, the windshield wiper motor activates the internal run/park relay coil which sends voltage through the internal high/low relay. The internal high/low relay remains deactivated, supplying the voltage to the low-speed brush of the windshield wiper motor. The windshield motor continues to operate until the internal Hall-effect sensor senses the magnet (PARK position) and deactivates the internal run/park relay, which disconnects voltage from the wiper motor. The windshield wipers remain parked until the windshield wiper motor module completes a time-out and then repeats the intermittent windshield wiper cycle.

Washer System

The windshield washer system consists of the washer reservoir and washer pump. When WASH is selected on the multifunction switch, the windshield wiper motor module activates its integral washer relay which sends voltage to the washer pump to direct fluid to the windshield.

Software Safe Mode

The windshield wiper motor defaults to software safe mode when the run/park sensor does not sense the Hall-effect magnet inside the wiper motor. This can be caused by an obstruction of the windshield wipers, a binding linkage or loss of the Hall sensor signal. The motor continues to operate in a high/low-speed condition, and when turned off, the wipers immediately park on the windshield. If necessary, the wipers can be turned on and off until they return to the PARK position.

 Windshield Wiper Circuit Function Table

Inspection and Verification

1. Verify the customer concern.

2. Visually inspect for obvious signs of mechanical or electrical damage.

 Visual Inspection Chart

3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.

4. NOTE: The windshield wiper motor does not communicate on the network. The windshield wiper motor provides wiper on/off status directly to the SJB .

   NOTE: Make sure to use the latest scan tool software release.

   If the cause is not visually evident, connect the scan tool to the Data Link Connector (DLC).

5. NOTE: The Vehicle Communication Module (VCM) LED prove out confirms power and ground from the DLC are provided to the VCM .

   If the scan tool does not communicate with the VCM :
   • check the VCM connection to the vehicle.
   • check the scan tool connection to the VCM .
   • refer to Section 418-00 , No Power To The Scan Tool, to diagnose no power to the scan tool.

6. If the scan tool does not communicate with the vehicle:
   • verify the ignition key is in the ON position.
   • verify the scan tool operation with a known good vehicle.
   • refer to Section 418-00 to diagnose no response from the SJB .

7. Carry out the network test.
   • If the scan tool responds with no communication from one or more modules, refer to Section 418-00 .
   • If the network test passes, retrieve and record the Continuous Memory Diagnostic Trouble Codes (CMDTCs).

8. Clear the continuous DTCs and carry out the self-test diagnostics for the SJB .

9. If the DTCs retrieved are related to the concern, go to the Smart Junction Box (SJB) DTC Chart. For all other DTCs, refer to Section 419-10 .

10. If no DTCs related to the concern are retrieved, GO to Symptom Chart .

DTC Chart

Smart Junction Box (SJB) DTC Chart

Symptom Chart

Pinpoint Tests

Pinpoint Test A: The Wipers Are Inoperative

Refer to Wiring Diagrams Cell 81 , Wipers and Washers for schematic and connector information.

Normal Operation

When the ignition switch is in the RUN or ACCESSORY position, voltage is supplied to the wiper relay coil through circuit CBP45 (YE). The wiper relay coil is grounded at all times through circuit GD129 (BK/YE). Voltage is supplied to the wiper relay switch through circuit SBB09 (RD). When the wiper relay is activated, voltage is supplied to the wiper motor through circuit CRW03 (VT/WH) and through CBP45 (YE) when the ignition switch is in the RUN or ACCESSORY position. The wiper motor is grounded through circuits GD129 (BK/YE) and GD123 (BK/GY). The multifunction switch is grounded through circuit GD116 (BK/VT). The multifunction switch sends open and ground input signals to the wiper motor through circuits CRW17 (GN/VT), CRW18 (VT/WH), CRW19 (BU/OG) and CRW08 (VT/OG) in order to activate the wiper motor to the requested modes.

This pinpoint test is intended to diagnose the following:
• Fuse(s)
• Wiper motor
• Wiper relay
• Multifunction switch
• Wiring, terminals or connectors

PINPOINT TEST A: THE WIPERS ARE INOPERATIVE

NOTICE: Use the correct probe adapter(s) from the Flex Probe Kit when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

Pinpoint Test B: The Wipers Stay On Continuously

Refer to Wiring Diagrams Cell 81 , Wipers and Washers for schematic and connector information.

Normal Operation

Under normal operation, the windshield wiper motor receives open and ground inputs from the multifunction switch through circuits CRW17 (GN/VT), CRW18 (VT/WH), CRW19 (BU/OG) and CRW08 (VT/OG) to activate the wipers to the appropriate modes. Mode of operation is dependent on the signal(s) received from the multifunction switch.

This pinpoint test is intended to diagnose the following:
• Wiring, terminals or connectors
• Windshield wiper motor
• Multifunction switch

PINPOINT TEST B: THE WIPERS STAY ON CONTINUOUSLY

NOTICE: Use the correct probe adapter(s) from the Flex Probe Kit when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

Pinpoint Test C: The High/Low Wiper Speeds Do Not Operate Correctly

Refer to Wiring Diagrams Cell 81 , Wipers and Washers for schematic and connector information.

Normal Operation

Under normal operation, the windshield wiper motor receives open and ground inputs from the multifunction switch through circuits CRW17 (GN/VT), CRW18 (VT/WH), CRW19 (BU/OG) and CRW08 (VT/OG) to activate the wipers to the appropriate modes. Mode of operation is dependent on the signal(s) received from the multifunction switch.

This pinpoint test is intended to diagnose the following:
• Wiring, terminals or connectors
• Windshield wiper motor
• Multifunction switch

PINPOINT TEST C: THE HIGH/LOW WIPER SPEEDS DO NOT OPERATE CORRECTLY

NOTICE: Use the correct probe adapter(s) from the Flex Probe Kit when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

Pinpoint Test D: The Intermittent Wiper Speed Does Not Operate Correctly

Refer to Wiring Diagrams Cell 81 , Wipers and Washers for schematic and connector information.

Normal Operation

Under normal operation, the windshield wiper motor receives open and ground inputs from the multifunction switch through circuits CRW17 (GN/VT), CRW18 (VT/WH), CRW19 (BU/OG) and CRW08 (VT/OG) to activate the wipers to the appropriate modes. Mode of operation is dependent on the signal(s) received from the multifunction switch.

This pinpoint test is intended to diagnose the following:
• Wiring, terminals or connectors
• Windshield wiper motor
• Multifunction switch

PINPOINT TEST D: THE INTERMITTENT WIPER SPEED DOES NOT OPERATE CORRECTLY

NOTICE: Use the correct probe adapter(s) from the Flex Probe Kit when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

Pinpoint Test E: The Washer Pump is Inoperative

Refer to Wiring Diagrams Cell 81 , Wipers and Washers for schematic and connector information.

Normal Operation

During normal operation, the windshield wiper motor receives voltage through Battery Junction Box (BJB) fuse 9 (30A), circuit SBB09 (RD) and through Smart Junction Box (SJB) fuse 45 (5A), circuit CBP45 (YE) when the ignition switch is in the RUN or ACC positions. Ground is provided to the windshield wiper motor through circuits GD129 (BK/YE) and GD123 (BK/GY). The internal run/park and internal high/low relays are contained in the wiper motor electronics. Mode of operation is dependent on the signal(s) received from the multifunction switch. When the correct input is received from the multifunction switch, the windshield wiper motor activates the washer pump by providing power through circuit CRW14 (BU/WH). Ground is provided to the washer pump through circuit GD123 (BK/GY).

This pinpoint test is intended to diagnose the following:
• Wiring, terminals or connectors
• Multifunction switch
• Washer pump
• Windshield wiper motor

PINPOINT TEST E: THE WASHER PUMP IS INOPERATIVE

NOTICE: Use the correct probe adapter(s) from the Flex Probe Kit when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

Pinpoint Test F: The Headlamps Do Not Illuminate When the Wipers are On

Normal Operation

The Smart Junction Box (SJB) monitors the status of the wipers through circuit CRW01 (WH). When the headlamp control switch is in the AUTOLAMP position and the wipers are on, the wiper motor module will pull the voltage reference signal low. Within 10 seconds, the SJB will activate the headlamps.

• DTC B2008 Wipers On Signal Circuit Short to Ground — Short to ground on wiper motor on input circuit.

This pinpoint test is intended to diagnose the following:
• Wiring, terminals or connectors
• Wiper motor
• SJB

PINPOINT TEST F: THE HEADLAMPS DO NOT ILLUMINATE WHEN THE WIPERS ARE ON

NOTICE: Use the correct probe adapter(s) from the Flex Probe Kit when making measurements. Failure to use the correct probe adapter(s) may damage the connector.