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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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