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 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 Fuel Pump and Level Sensor Assembly
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 Control Module References for scan tool information
Circuit/System Verification
1. Ignition ON, windshield wiper/washer switch in the OFF position, verify the scan tool Windshield Washer Switch parameter is Inactive.
• If not the specified value, refer to Windshield Wiper Washer System Malfunction Windshield Wiper Washer System 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 the Windshield Wiper/Washer Switch Circuit Test.
3. Wiper switch in the OFF position, verify the scan tool Windshield Wiper High Speed Switch parameter is Inactive.
• If not the specified value, refer to the Windshield Wiper/Washer Switch Circuit Test.
4. Wiper switch in the LO position, verify the scan tool Windshield Wiper Switch parameter is Low.
• If not the specified value, refer to the Windshield Wiper/Washer Switch Circuit Test.
5. Wiper switch in the HIGH position, verify the scan tool Windshield Wiper High Speed Switch parameter is Active.
• If not the specified value, refer to the Windshield Wiper/Washer Switch Circuit Test.
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 windshield 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 low speed, refer to the Windshield Wiper Motor Circuit Test.
8. Wiper switch in the HIGH position, verify the windshield wipers are cycling at high speed.
• If the wipers are not operating at high speed, refer to the Windshield Wiper Motor Circuit Test.
9. 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 or the wipers do not park, refer to the Wiper Park Circuit Test.
Circuit/System Testing
Windshield Wiper/Washer Switch Circuit Test
1. Ignition OFF, disconnect the harness connector at the S82 windshield wiper/washer switch.
2. Verify a test lamp illuminates between low reference terminal 2 and B+.
• If the test lamp does not illuminate, test the low reference circuit for an open/high resistance. If the circuit test normal, replace the K9 BCM.
3. Ignition ON, verify the scan tool Windshield Wiper Switch parameter is Off.
• If not the specified value, test the signal circuit terminal 2 for a short to ground. If the circuit tests normal, replace the K9 BCM.
4. Verify the scan tool Wiper High Speed Switch parameter is Inactive.
• If not the specified value, test the signal circuit terminal 5 for a short to ground. If the circuit tests normal, replace the K9 BCM.
5. Install a 3 A fused jumper wire between the signal circuit terminal 2 and ground. Verify the scan tool Windshield Wiper Switch parameter is Switch Fault.
• 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 K9 BCM.
6. Install a 3 A fused jumper wire between the signal circuit terminal 5 and ground. Verify the scan tool Wiper High Speed Switch parameter is Active.
• 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 K9 BCM.
7. If all circuits test normal, test or replace the S82 windshield wiper/washer switch.
Windshield Wiper Motor Circuit Test
1. Ignition OFF, disconnect KR12B windshield wiper relay.
2. Test for less than 10 ohms 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 10 ohms 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 that a test lamp illuminates between the B+ circuit terminal 87 and ground.
• If the test lamp does not illuminate, replace the X50A underhood fuse block.
5. Connect a test lamp between the control circuit terminal 86 and the ground circuit terminal 85.
6. Command the low speed wipers ON and OFF using the S82 windshield wiper/washer 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 K9 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 K9 BCM.
7. Ignition OFF, disconnect the KR12C windshield wiper speed control relay.
8. Test for less than 5 ohms between the control circuit terminal 30 at the KR12B windshield wiper relay and the control circuit terminal 30 at the KR12C windshield wiper speed control relay.
• If greater than the specified range, replace the X50A underhood fuse block.
9. Connect the KR12B windshield wiper relay.
10. Test for less than 5 ohms between the control circuit terminal 30 of the KR12C windshield wiper speed control relay and ground.
• If greater than the specified range, test or replace the KR12B windshield wiper relay.
11. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 85 and ground.
• If the test lamp does not illuminate, replace the X50A underhood fuse block.
12. Connect a test lamp between the control circuit terminal 30 and ground.
13. Command the low speed wipers ON using the S82 windshield wiper/washer switch. The test lamp should illuminate.
• If the test lamp does not illuminate, replace the KR12B windshield wiper relay.
14. Connect a test lamp between the B+ circuit terminal 85 and the control circuit terminal 86.
15. Command the high speed wipers ON using the S82 windshield wiper/washer switch. The test lamp should turn ON and OFF when changing between commanded states.
• If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the K9 BCM.
• 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 BCM.
16. Ignition OFF, connect the KR12C windshield wiper speed control relay. Disconnect the harness connector at the M75 windshield wiper motor.
17. Test for less than 5 ohms between the ground circuit terminal 3 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 1 and ground.
19. Ignition ON, command the low speed wipers ON and OFF using the S82 windshield wiper/washer 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, 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 2 and ground.
21. Command the high speed wipers ON and OFF using the S82 windshield wiper/washer 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, 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. If all circuits test normal, test or replace the M75 windshield wiper motor.
Wiper Park Circuit Test
1. Ignition OFF, disconnect the harness connector at the M75 windshield wiper motor.
2. Test for less than 5 ohms between the ground circuit terminal 3 and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, test for greater than 10 V between signal circuit terminal 4 and ground.
• If not the specified value, test the signal circuit for a short to ground or open/high resistance. If the circuit tests normal, test or replace the K9 BCM.
4. If the circuit tests normal, test or replace the M75 windshield wiper motor.
Component Testing
Windshield Wiper/Washer Switch Malfunction
1. Ignition OFF, disconnect the harness connector at the S82 windshield wiper/washer switch.
2. With the wiper switch in the HIGH position, test for less than 2 ohms between the low reference terminal 1 and the signal terminal 5.
• If greater than the specified range, replace the S82 windshield wiper/washer switch.
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.
3. While cycling the wiper switch through each delay and speed position, test for the specified resistance between the low reference terminal 1 and the signal terminal 2.
If any switch position is not within the specified range, replace the S82 windshield wiper/washer switch.
Windshield Wiper Motor
1. Ignition OFF, disconnect the harness connector at the M75 windshield wiper motor.
2. Install a 25 A fused jumper wire between B+ and the control terminal 1. Install a jumper wire between the terminal 3 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 M75 windshield wiper motor.
4. Install a 25 A fused jumper wire between B+ and the control terminal 2. Install a jumper wire between the terminal 3 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 M75 windshield wiper motor.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Relay Replacement (Within an Electrical Center) Relay Replacement (Within an Electrical Center)Relay Replacement (Attached to Wire Harness) Relay Replacement (Attached to Wire Harness)
* Underhood Electrical Center or Junction Block Replacement Service and Repair
* Windshield Wiper and Washer Switch Replacement (LHD) Service and Repair
* Control Module References Control Module References for BCM replacement, programming and setup