Windshield Wiper System Malfunction Front

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 different PCB relays which control the desired wiper speed, high or low.

Schematic Reference

Wiper/Washer Schematics

Connector End View Reference

Wiper/Washer Connector End Views

Description and Operation

Wiper/Washer System Description and Operation

Electrical Information Reference

Scan Tool Reference

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 Washer 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 Windshield Wiper Switch Circuit Malfunction.

3. Wiper switch in the OFF position, verify the scan tool Wiper High Speed Switch parameter is Inactive.

⇒	If not the specified value, refer to Windshield Wiper Switch Circuit Malfunction.

4. Wiper switch in the LO position, verify the scan tool Windshield Wiper Switch parameter is Low.

⇒	If not the specified value, refer to Windshield Wiper Switch Circuit Malfunction.

5. Wiper switch in the HIGH position, verify the scan tool Wiper High Speed Switch parameter is Active

⇒	If not the specified value, refer to Windshield Wiper Switch Circuit Malfunction.

6. Wiper switch in the INT position, verify the scan tool Windshield Wiper Switch parameter is Intermittent.

⇒	If not the specified value, test or replace the Windshield Wiper Washer Switch.

7. Wiper switch in the INT position, observe the scan tool Wiper Delay Setting 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 the delay setting does not match the parameter, test or replace the Windshield Wiper Washer Switch.

8. 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.

9. 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.

10. 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.

Windshield Wiper Switch Circuit Malfunction

1. Ignition OFF, disconnect the harness connector at the windshield wiper switch.
2. Ignition OFF, test for less than 20 ohms of resistance between the ground circuit terminal D and ground.

⇒	If greater than the specified range, test the ground circuit for 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 signal circuit terminal E for a short to ground. If the circuit tests normal, replace the BCM.

4. Verify the scan tool Wiper High Speed Switch parameter Inactive

⇒	If not the specified value, test the signal circuit terminal C for a short to ground. If the circuit tests normal, replace the BCM.

5. Install a 3A fused jumper wire between the signal circuit terminal E 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 BCM.

6. Install a 3A fused jumper wire between the signal circuit terminal C 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 BCM.

7. If all circuits test normal, test or replace the Windshield Wiper Washer Switch.

Windshield Wiper Motor Circuit Malfunction.

1. Ignition OFF, disconnect the C2 harness connector at the underhood fuse block.
2. Connect a test lamp between the control circuit terminal 32 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 the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.

4. Connect a test lamp between the control circuit terminal 31 and B+.
5. Command the high 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 ground. If the circuit tests normal, replace the 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 BCM.

6. Ignition OFF, connect the C2 harness connector at the underhood fuse block. Disconnect the harness connector at the windshield wiper motor.
7. Test for less than 20 ohms of resistance between the ground circuit terminal C and ground.

⇒	If greater than the specified range, test the ground circuit for an open/high resistance.

8. Connect a test lamp between the control circuit terminal E and ground.
9. 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 ground. 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 voltage or an open/high resistance. If the circuit tests normal, replace the underhood fuse block.

10. Connect a test lamp between the control circuit terminal D and ground.
11. Ignition ON, command the high 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 ground. 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 voltage or an open/high resistance. If the circuit tests normal, replace the underhood fuse block.

12. Verify a test lamp illuminates between the signal circuit terminal B and ground.

⇒	If the test lamp does not illuminate, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.

13. If all circuits test normal, test or replace the windshield wiper motor.

Windshield Wiper Washer Switch

1. With the wiper switch in the HIGH position, test for less than 2 ohms of resistance between the ground terminal D and the signal terminal C.

⇒	If greater than the specified range, replace the windshield wiper washer switch.

2. While cycling the wiper switch through each delay and speed position, test for the specified resistance between the ground terminal D and the signal 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.

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 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.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure

Windshield Wiper System Malfunction Rear

The rear wiper is controlled based on an input from the rear wiper/washer switch. When the wiper portion of the rear wiper/washer switch is closed, a ground signal is provided to the rear window wiper motor indicating rear wiper operation is request. The rear wiper motor receives B+ voltage from the I/P fuse block and accessory voltage from the BCM. The rear wiper motor also monitors the state of the liftgate ajar indicator and will suspend rear wiper operating when the liftgate is open.

Schematic Reference

Wiper/Washer Schematics

Connector End View Reference

Wiper/Washer Connector End Views

Description and Operation

Wiper/Washer System Description and Operation

Electrical Information Reference

Scan Tool Reference

1. Ignition ON, liftgate closed, verify the liftgate ajar indicator is not illuminated.

⇒	If the liftgate ajar indicator is illuminated, refer to Rear Hatch/Gate Ajar Indicator Always On

2. Command the rear wiper ON using the rear wiper/washer switch. The rear wiper should activate.

1. Ignition OFF, disconnect the harness connector at the rear wiper/washer switch.
2. Test for less than 5 ohms of resistance between the ground circuit terminal 1 and ground.

⇒	If greater than the specified range, test the ground circuit for an open/high resistance.

3. Reconnect the harness connector at the rear wiper/washer switch. Disconnect the harness connector at the rear window wiper motor.
4. Test for less than 20 ohms of resistance between the ground circuit terminal A and ground.

⇒	If greater than the specified range, test the ground circuit for an open/high resistance.

5. Ignition ON, verify a test lamp illuminates between the B+ circuit terminal C and ground.

⇒	If the test lamp does not illuminate, test he B+ circuit for an open/high resistance. If the RR WPR fuse is open, test the B+ circuit for a short to ground. If the circuit tests normal, test or replace the rear window wiper motor.

6. Verify a test lamp illuminates between the ignition circuit terminal D and ground.

⇒	If the test lamp does not illuminate, test he ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.

7. Ignition OFF, liftgate open, test for less than 5 ohms of resistance between the signal circuit terminal F and ground.

⇒	If greater than the specified range, test the signal circuit for an open/high resistance. If the circuit tests normal, refer to Rear Hatch/Gate Ajar Indicator Always On .

8. Rear wiper switch closed, test for less than 10 ohms of resistance between the signal circuit terminal B and ground.

⇒	If greater than the specified range, test the signal circuit for an open/high resistance. If the circuit tests normal, test or replace the rear wiper/washer switch.

9. If all circuits test normal, test or replace the rear window wiper motor.

Rear Wiper/Washer Switch

1. With the rear wiper switch in the open position, test for infinite resistance between the ground terminal 1 and the signal terminal 2.

⇒	If not the specified value, replace the rear wiper/washer switch.

2. With the rear wiper switch in the closed position, test for less than 2 ohms of resistance between the ground terminal 1 and the signal terminal 2.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure

Liftgate Wiper Motor Replacement