Wiper Mist, Delay 1-5, and Low are all low speed wiper motor functions that are controlled by the body control module (BCM). When the wiper switch is placed in one of the LOW speed wiper modes, ground is applied through the switch contacts a series of internal resistors and the wiper switch low signal circuit to the BCM. In response to this signal, the BCM energizes the WPR Relay 70 by applying battery voltage through the wiper relay control circuit to the coil side of the relay. This allows battery positive voltage from the WPR fuse to flow through the switch input side of the WPR Relay 70 and out to the switch input side of the WPR Relay 52. Since the WPR Relay 52 is de-energized and its switch contacts are normally closed to the low speed control circuit of the windshield wiper motor, the motor will operate at low speed.

When the wiper switch is placed in the HIGH speed position, Battery voltage is applied through the switch contacts and the wiper switch high signal circuit directly to the coil side of the WPR Relay 52. With the wiper high relay energized and its switch contacts closed to the high speed control circuit of the wiper motor, the motor will operate at high speed.

1. A short to ground in the following circuits will open the WPR/WSHR fuse:

•	Ignition 1 voltage

•	Windshield wiper motor relay coil supply voltage

•	Windshield wiper switch high signal

•	Windshield wiper motor low speed control

•	Windshield wiper motor high speed control

2. A short to B+ on any of the wiper/washer switch signal circuits will open the ground trace in the wiper switch.

Schematic Reference

Wiper/Washer Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Wiper/Washer System Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

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 Wiper High Speed 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 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 not the specified value, test or replace the Multifunction 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.

Multifunction Switch Circuit Malfunction

1. Ignition OFF, disconnect the harness connector at the windshield wiper washer multifunction switch.
2. Ignition ON, test for B+ at the windshield wiper washer multifunction 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 Multifunction Switch.

Wipers Do Not Park Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the windshield wiper motor.
2. Ignition ON, verify the scan tool BCM Wiper Park Switch parameter is Inactive.

⇒	If not Inactive, test the signal circuit terminal B for a short to ground. If the circuit tests normal, replace the body control module.

3. Install a 3-amp fused jumper wire between the wiper motor park switch signal circuit terminal B and ground. Verify the scan tool Wiper Park Switch parameter is Active.

⇒	If not Active, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the body control module.

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

Windshield Wiper Motor Circuit Malfunction

1. Ignition OFF, disconnect WPR Relay 70.
2. Test for less than 20 ohms of resistance 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 20 ohms of resistance 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 multifunction 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 WPR Relay 52.
8. Test for less than 2 ohms of resistance between the control circuit terminal 30 at the WPR relay and the control circuit terminal 30 at the WPR HI relay.

⇒	If greater than the specified range, replace the underhood fuse block.

9. Connect the WPR Relay 52.
10. Test for less than 20 ohms of resistance between the control circuit terminal 30 and ground.

⇒	If greater than the specified range, test or replace the WPR Relay 52.

11. Ignition ON, verify a test lamp illuminates between the B+ circuit terminal 85 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 and the ground circuit terminal 87.
13. Using the multifunction switch, command the low speed wipers ON. The test lamp should turn illuminate.

⇒	If the test lamp does not illuminate, replace the WPR Relay 52.

14. Install a test lamp between the B+ circuit terminal 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 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.

16. Ignition OFF, connect the WPR Relay 52. Disconnect the harness connector at the windshield wiper motor.
17. 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.

18. Connect a test lamp between the control circuit terminal D and ground.
19. Using the multifunction 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 WPR Relay 70.

⇒	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 WPR Relay 70.

20. Connect a test lamp between the control circuit terminal C 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 WPR Relay 52.

⇒	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 WPR Relay 52.

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.

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 ohms of resistance 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.

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 D and 12 volts. Install a jumper wire between the ground terminal A 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 C and 12 volts. Install a jumper wire between the ground terminal A 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.