Circuit/System Testing

Multifunction Switch Circuit Malfunction

1. Ignition OFF, disconnect the X1 harness connector at the multifunction switch.
2. Ignition OFF, test for less than 20 Ω between the ground circuit terminal 7 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 4 (without N38) or terminal 10 (with N38) 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 5 (without N38) or terminal 9 (with N38) for a short to ground. If the circuit tests normal, replace the BCM.
5. Install a 3 A fused jumper wire between the signal circuit terminal 4 (without N38) or terminal 10 (with N38) 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 3 A fused jumper wire between the signal circuit terminal 5 (without N38) or terminal 9 (with N38) 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 multifunction switch.

Windshield Wiper Motor Circuit Malfunction

1. Ignition OFF, disconnect windshield wiper relay.
2. Test for less than 20 Ω 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 Ω 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 windshield wiper speed control relay.
8. Test for less than 2 Ω between the control circuit terminal 30 at the windshield wiper relay and the control circuit terminal 30 at the windshield wiper speed control relay.
   • If greater than the specified range, replace the underhood fuse block.
9. Connect the windshield wiper relay.
10. Test for less than 20 Ω between the control circuit terminal 30 and ground.
    • If greater than the specified range, test or replace the windshield wiper relay.
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 ground.
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 windshield wiper relay.
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 windshield wiper speed control replay. Disconnect the harness connector at the windshield wiper motor.
17. Test for less than 20 Ω between the ground circuit terminal 4 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 2 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 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 windshield wiper speed control relay.
20. Connect a test lamp between the control circuit terminal 1 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 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 windshield wiper speed control relay.
22. Wipers OFF, test for greater than 12V between the signal circuit terminal 3 and ground.
    • If less than the specified range, test the signal circuit for a short to ground or open/high resistance. If the circuit tests normal, test or replace the windshield wiper motor.
23. If all circuits test normal, test or replace the windshield wiper motor.