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 three 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 windshield washer switch signal circuit is used to determine washer operation. The windshield wiper motor park operation is controlled by the BCM. The BCM receives an input from the park switch to determine wiper blade position. When the wiper blades are at the bottom of the windshield glass in park position the wiper park switch will open and the circuit will be pulled up to B+ by the BCM. The park signal will be pulled to ground by the wiper motor park switch while the wiper blades are not in the park position.
The BCM controls the windshield wiper motor through 2 output controls, controlling 2 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 End Views By Name
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. Ignition ON, wiper switch in the OFF position, verify the scan tool Windshield Washer Switch parameter is Inactive.
• If not the specified value, refer to Multifunction Switch Circuit Malfunction.
2. Wiper switch in the OFF position, verify the scan tool Windshield Wiper Switch parameter is Off.
• If not the specified value, refer to Multifunction Switch Circuit Malfunction.
3. Wiper switch in the OFF position, verify the scan tool Wiper Motor Relay Status parameter is OFF.
• If not the specified value, refer to Multifunction Switch Circuit Malfunction.
4. Wiper switch in the LO position, verify the scan tool Windshield Wiper Switch parameter is Low/Mist/High.
• If not the specified value, refer to Multifunction Switch Circuit Malfunction.
5. Wiper switch in the HIGH position, verify the scan tool Windshield Wiper Switch parameter is Low/Mist/High.
• If not the specified value, refer to Multifunction Switch Circuit Malfunction.
6. Wiper switch in the INT position, observe the scan tool Windshield Wiper Switch parameter while cycling the delay adjustment switch from long delay to short delay. The parameter should cycle between D1 and D5 as each delay position is selected.
• If not the specified value, test or replace the wiper/washer switch.
7. Wiper switch in the LO position, verify the windshield wipers are cycling at the low speed.
• If the wipers are not operating at the low speed, refer to Windshield Wiper Motor Circuit Malfunction.
8. Wiper switch in the HIGH position, verify the windshield wipers are cycling at the high speed.
• If the wipers are not operating at the low speed, refer to Windshield Wiper Motor Circuit Malfunction.
9. Wiper 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 the delay does not change as specified, refer to Windshield Wiper Motor Circuit Malfunction.
Circuit/System Testing
Multifunction Switch Circuit Malfunction
1. Ignition OFF, disconnect the harness connector at the windshield wiper/washer switch.
2. Ignition ON, test for B+ at the windshield wiper/washer switch accessory voltage circuit terminal D
• If not the specified value, test the accessory voltage circuit for a short to ground or an open/high resistance. If the circuit test normal, replace the BCM.
3. Ignition ON, verify the scan tool Windshield Wiper Switch parameter is Off.
• If not the specified value, test the windshield wiper switch signal 1 circuit terminal E for a short to ground. If the circuit tests normal, replace the BCM.
4. Install a 3A fused jumper wire between the windshield wiper switch signal 1 circuit terminal E and B+. Verify the scan tool Windshield Wiper Switch parameter is Low/Mist/High.
• If not the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
5. Install a 3A fused jumper wire between the windshield wiper switch signal 2 circuit terminal C and ground. Verify the scan tool Windshield Wiper Switch parameter Low/Mist/High.
• If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
6. If all circuits test normal, test or replace the wiper/washer switch.
Windshield Wiper Motor Circuit Malfunction
1. Ignition OFF, disconnect wiper 1 relay.
2. Test for less than 20 ohm between the ground circuit terminal 86 and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Test for less than 20 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 85 and the ground circuit terminal 86.
6. Using the 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 BCM.
• 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 BCM.
7. Ignition OFF, disconnect the WIPER 2 relay.
8. Test for less than 2 ohm between the control circuit terminal 30 at the WIPER 2 relay and the control circuit terminal 30 at the WPR 1 relay.
• If greater than the specified range, replace the underhood fuse block.
9. Connect the WPR 1 relay.
10. Test for less than 20 ohm between the control circuit terminal 30 and ground.
• If greater than the specified range, test or replace the WIPER 1 relay.
11. Test for less then 20 ohm between the ground circuit terminal 85 and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
12. Install a test lamp between the control circuit terminal 30 and the ground circuit terminal 85.
13. Using the wiper/washer switch, command the low speed wipers ON. The test lamp should turn illuminate.
• If the test lamp does not illuminate, replace the WIPER 1 relay.
14. Install a test lamp between the ground circuit terminal 85 and the control circuit terminal 86.
15. Using the multifunction 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 wiper/washer switch.
• 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 wiper/washer switch.
16. Ignition OFF, connect the WIPER 2 Relay. Disconnect the harness connector at the windshield wiper motor.
17. Test for less than 20 ohm between the ground circuit terminal C and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
18. Connect a test lamp between the control circuit terminal E and ground.
19. Using the 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 WIPER 2 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 WIPER 2 relay.
20. Connect a test lamp between the control circuit terminal D and ground.
21. Using the multifunction 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 WIPER 2 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 WIPER 2 relay.
22. Verify a test lamp illuminates between the signal circuit terminal B and ground.
• If the test lamp does not illuminate, replace the BCM.
23. If all circuits test normal, test or replace the windshield wiper motor.
Component Testing
Multifunction Switch
1. Disconnect the windshield wiper washer switch harness connector at the multifunction switch.
2. With the wiper switch in the HIGH position, test for less than 2 ohm between the windshield wiper switch signal 1 terminal E and the windshield wiper switch signal 2 terminal C.
• If greater than the specified range, replace the windshield wiper washer switch.
3. While cycling the wiper switch through each delay and speed position, test for the specified resistance between the accessory voltage terminal D and the signal 1 terminal E.
Important: 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 windshield wiper washer switch.
Windshield Wiper Motor
1. Ignition OFF, disconnect the harness connector at the windshield wiper motor.
2. Install a 25A fused jumper wire between the control terminal E and 12 volts. Install a jumper wire between the ground terminal C and ground.
3. Verify the wiper motor is operating in the low speed mode.
• If the wiper motor is not in the low speed mode, replace the windshield wiper motor.
4. Install a 25A fused jumper wire between the control terminal D and 12 volts. Install a jumper wire between the ground terminal C and ground.
5. Verify the wiper motor is operating in the high speed mode.
• If the wiper motor is not in the high speed mode, replace the windshield wiper motor.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure
* Relay Replacement (Attached to Wire Harness) Relay Replacement (Attached to Wire Harness)Relay Replacement (Within an Electrical Center) Relay Replacement (Within an Electrical Center)
* Turn Signal Multifunction Switch Replacement Turn Signal Multifunction Switch Replacement
* Windshield Wiper Motor Replacement Windshield Wiper Motor Replacement
* Underhood Electrical Center or Junction Block Replacement Underhood Electrical Center or Junction Block Replacement
* Control Module References Programming and Relearning for BCM replacement, setup, and programming