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Home >> Hummer >> 2008 >> H3 Base, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 175 (Wiper System & Washer System) >> Diagnostic Information and Procedures >> Windshield Wiper System Malfunction >> Circuit/System Testing
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Circuit/System Testing

WARNING: This page is about a different car, the 2008 Cadillac STS. However, it is still accessible from the selected car via links, so may be relevant.

Multifunction Switch Circuit/System Testing

  1. Ignition OFF, disconnect the C1 harness connector at the turn signal/multifunction switch.
  2. Ignition OFF, test for less than 15.0 ohms of resistance between the ground circuit terminal H and ground.
    • If greater than 15.0 ohms, test the ground circuit for an open/high resistance. If the circuit tests normal, test or replace the body control module.
  3. Verify the scan tool Windshield Wiper Switch parameter is Off.
    • If not Off, test the signal circuit terminal L for a short to ground. If the circuit tests normal, test or replace the body control module.
  4. Verify the scan tool Wiper High Speed Switch parameter is Inactive.
    • If not Inactive, test the signal circuit terminal K for a short to ground. If the circuit tests normal, test or replace the body control module.
  5. Install a 3A fused jumper wire between the signal circuit terminal L and ground. Verify the scan tool Windshield Wiper Switch parameter is Switch Fault.
    • If not Switch Fault, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, test or replace the body control module.
  6. Install a 3A fused jumper wire between the signal circuit terminal K and ground. Verify the scan tool Wiper High Speed Switch parameter is Active.
    • If not Active, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, test or replace the body control module.
  7. If all circuits test normal, test or replace the turn signal/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 C for a short to ground. If the circuit tests normal, test or replace the body control module.
  3. Install a 3A fused jumper wire between the wiper motor park switch signal circuit terminal C 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, test or replace the windshield wiper motor.

Wiper Motor Circuit/System Testing

  1. Ignition OFF, remove the WPR Relay from the underhood fuse block.
  2. Test for less than 5.0 ohms of resistance between the wiper relay ground circuit terminal 86 and ground.
    • If greater than 5.0 ohms, test the ground circuit for an open/high resistance.
  3. Connect a test lamp between the control circuit terminal 85 and ground.
  4. Ignition ON, command the Wiper Relay ON and OFF with a scan tool. 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 body control module.
    • 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 body control module.
  5. Ignition OFF, install the WPR Relay.
  6. Remove the WPR HI Relay from the underhood fuse block.
  7. Connect a test lamp between the supply voltage circuit terminal 30 and ground.
  8. Ignition ON, command the Wiper Relay ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
    • If the test lamp is always ON, test the supply voltage circuit for a short to voltage. If the circuit tests normal, replace the WPR Relay.
    • If the test lamp is always OFF, test the supply voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the WPR Relay.
  9. Connect a test lamp between the control circuit terminal 86 and battery voltage.
  10. Ignition ON, command the Wiper High Speed Relay ON and OFF with a scan tool. 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, test or replace the body control module.
    • 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, test or replace the body control module.
  11. Ignition OFF, replace the WPR HI Relay.
  12. Disconnect the harness connector at the wiper motor.
  13. Test for less than 1.0 ohm of resistance between the wiper motor ground circuit terminal D and ground.
    • If greater than 1.0 ohm, test the ground circuit for an open/high resistance.
  14. Connect a test lamp between the control circuit terminal B and ground.
  15. Ignition ON, command the Wiper Relay ON and OFF with a scan tool. 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 WPR HI 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, replace the WPR HI Relay.
  16. Connect a test lamp between the control circuit terminal A and ground.
  17. Place the wiper switch in the LOW speed position. Command the Wiper High Speed Relay ON and OFF with a scan tool. 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 WPR HI 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, replace the WPR HI Relay.
  18. If all circuits test normal, test or replace the Windshield Wiper Motor.
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