Windshield Wiper System Malfunction
Windshield Wiper System Malfunction
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.
Diagnostic Fault Information
Circuit/System Description
The Body Control Module (BCM) controls the wiper motor based on input from the windshield wiper/washer switch. The BCM monitors the wiper/washer switch through two separate signal circuits and a ground circuit. The windshield wiper switch high signal circuit is used to determine high speed wiper operation, the windshield wiper switch low signal is used to determine low speed, intermittent, and mist operation through the use of a resistor ladder, and the windshield washer switch signal circuit is used to determine washer operation.
The BCM controls the windshield wiper motor through two output controls, controlling two relays which determine the desired wiper speed, high or low.
Reference Information
Schematic Reference
Wiper/Washer Schematics (Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
Wiper/Washer System Description and Operation (Description and Operation)
Electrical Information Reference
* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing For Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Verification
1. S80 Window Wiper/Washer Switch in the LOW position, verify the windshield wipers are cycling at low speed.
2. S80 Window Wiper/Washer Switch in the HIGH position, verify the windshield wipers are cycling at high speed.
3. S80 Window Wiper/Washer Switch in the INT position, cycling the delay adjustment switch from long delay to short delay. Verify the wiper delay time decreases from long delay to short delay as each delay position is selected. If equipped with Rain Sensor, spray some water on the windshield.
Circuit/System Testing
Multifunction Switch Malfunction
1. Ignition OFF, disconnect the X1 harness connector at the S80 Window Wiper/Washer Switch.
2. Ignition OFF, test for less than 5 ohm between the ground circuit terminal 2 and ground.
• If greater than the specified value, test the ground circuit for an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module.
3. If all circuits test normal, test or replace the S80 Window Wiper/Washer Switch.
Windshield Wiper Motor Malfunction
1. Ignition OFF, disconnect KR12B Windshield Wiper Relay.
2. Test for less than 5 ohm between the ground circuit terminal 85 and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Test for less than 5 ohm between the ground circuit terminal 87A and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
4. Ignition ON, verify a test lamp illuminates between the B+ circuit terminal 87 and ground.
• If the test lamp does not illuminate, test or replace the underhood fuse block.
5. Install a test lamp between the control circuit terminal 86 and the ground circuit terminal 85.
6. Using the S80 Window Wiper/Washer Switch, command the low speed wipers ON and OFF. The test lamp should turn ON and OFF as commanded.
• If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K9 Body Control Module.
• 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 K9 Body Control Module.
7. Ignition OFF, disconnect the KR12C Windshield Wiper Speed Control Relay.
8. Test for less than 5 ohm between the control circuit terminal 30 at the KR12B Windshield Wiper Relay socket and the control circuit terminal 30 at the KR12C Windshield Wiper Speed Control Relay socket.
• If greater than the specified range, replace the underhood fuse block.
9. Connect the KR12B Windshield Wiper Relay.
10. Test for less than 5 ohm between the control circuit terminal 30 from the KR12C Windshield Wiper Speed Control Relay socket and ground.
• If greater than the specified range, test or replace the KR12B Windshield Wiper Relay.
11. Ignition ON, verify a test lamp illuminates between the B+ circuit terminal 85 from the KR12C Windshield Wiper Speed Control Relay socket and ground.
• If the test lamp does not illuminate, test or replace the underhood fuse block.
12. Install a test lamp between the control circuit terminal 30 from the KR12C Windshield Wiper Speed Control Relay socket and ground.
13. Using the S80 Window Wiper/Washer Switch, command the low speed wipers ON. The test lamp should illuminate.
• If the test lamp does not illuminate, replace the KR12B Windshield Wiper Relay.
14. Install a test lamp between the B+ circuit terminal from the KR12C Windshield Wiper Speed Control Relay socket and the control circuit terminal 86 from the KR12C Windshield Wiper Speed Control Relay socket.
15. Using the S80 Window Wiper/Washer Switch, command the high speed wipers ON and OFF. The test lamp should turn ON and OFF as commanded.
• If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the K9 Body Control Module.
• If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module.
16. Ignition OFF, connect the KR12C Windshield Wiper Speed Control Relay. Disconnect the harness connector X1 at the M75 Windshield Wiper Motor.
17. Test for less than 5 ohm between the ground circuit terminal D and ground.
• If greater than the specified value, test the ground circuit for an open/high resistance.
18. Connect a test lamp between the control circuit terminal B and ground.
19. Using the S80 Window Wiper/Washer Switch, command the low speed wipers ON and OFF. The test lamp should turn ON and OFF as commanded.
• If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, test or replace the KR12C Windshield Wiper Speed Control Relay.
• 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, test or replace the KR12C Windshield Wiper Speed Control Relay.
20. Connect a test lamp between the control circuit terminal A and ground.
21. Using the S80 Window Wiper/Washer Switch, command the high speed wipers ON and OFF. The test lamp should turn ON and OFF as commanded.
• If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, test or replace the KR12C Windshield Wiper Speed Control Relay.
• 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, test or replace the KR12C Windshield Wiper Speed Control Relay.
22. Ignition ON, wipers OFF, test for greater than 11 V between the signal circuit terminal C and ground.
• If less than 11 V, test the signal circuit for a short to ground or an open high resistance. If the circuit tests normal, replace the K9 Body Control Module.
23. If all circuits test normal, test or replace the M75 Windshield Wiper Motor.
Component Testing
Multifunction Switch - Static Test
1. Disconnect the X1 harness connector at the S80 Window Wiper/Washer Switch.
2. With the S80 Window Wiper/Washer Switch in the HIGH position, test for less than 5 ohm between the terminal 2 and the signal terminal 1.
• If greater than the specified value, replace the S80 Window Wiper/Washer Switch.
3. While cycling the S80 Window Wiper/Washer Switch through each delay and speed position, test for the specified resistance between the low reference terminal 2 and the signal terminal 3.
Note: If the switch tests open in any switch position other than OFF, test the signal circuits for a short to voltage before replacing the switch.
If any switch position is not within the specified range, replace the S80 Window Wiper/Washer Switch.
Windshield Wiper Motor - Dynamic Test
1. Ignition OFF, disconnect the harness connector at the M75 Windshield Wiper Motor.
2. Install a 25 A fused jumper wire between the control terminal B and 12 V. Install a jumper wire between the ground terminal D and ground.
3. Verify the M75 Windshield Wiper Motor is operating in the low speed mode.
• If the M75 Windshield Wiper Motor is not in the low speed mode, replace the M75 Windshield Wiper Motor.
4. Install a 25 A fused jumper wire between the control terminal A and 12 V. Install a jumper wire between the ground terminal D and ground.
5. Verify the M75 Windshield Wiper Motor is operating in the high speed mode.
• If the M75 Windshield Wiper Motor is not in the high speed mode, replace the M75 Windshield Wiper Motor.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Windshield Wiper Motor Replacement (Service and Repair)
* Relay Replacement (Attached to Wire Harness) (Relay Replacement (Attached to Wire Harness))Relay Replacement (Within an Electrical Center) (Relay Replacement (Within an Electrical Center))
* Windshield Wiper and Washer Switch Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for BCM replacement, setup, and programming