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Home >> Cadillac >> 2018 >> CT6 Plug-In >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Wiper/Washer Systems >> Wiper System And Washer System >> Diagnostic Information and Procedures >> Windshield Wiper System Malfunction >> Circuit/System Testing
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Circuit/System Testing

Windshield Wiper/Washer Switch Malfunction

  1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the S82 Windshield Wiper/Washer Switch. It may take up to 11 min for all vehicle systems to power down.
  2. Test for less than 10 Ω between the low reference circuit terminal 1 and ground.
    • If 10 Ω or greater 
    1. Ignition OFF/Vehicle OFF, disconnect the harness connector at the K9 Body Control Module.
    2. Test for less than 2 Ω in the low reference circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K9 Body Control Module.
    • Go to next step: If less than 10 Ω 
  3. Ignition ON/Vehicle in Service Mode.
  4. Verify the scan tool Windshield Wiper High Speed Switch parameter is Inactive.
    • If not Inactive 
    1. Ignition OFF/Vehicle OFF, disconnect the harness connector at the K9 Body Control Module.
    2. Test for infinite resistance between the signal circuit terminal 2 and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the K9 Body Control Module.
    • Go to next step: If Inactive 
  5. Install a 3 A fused jumper wire between the signal circuit terminal 2 and the low reference circuit terminal 1.
  6. Verify the scan tool Windshield Wiper High Speed Switch parameter is Active.
    • If not Active 
    1. Ignition OFF/Vehicle OFF, remove the jumper wire, disconnect the harness connector at the K9 Body Control Module, ignition ON/vehicle in Service Mode.
    2. Test for less than 1 V between the signal circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • Go to next step: If less than 1 V
    3. Test for less than 2 Ω in the signal circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K9 Body Control Module.
    • Go to next step: If Active 
  7. Test for greater than 8 V between the signal circuit terminal 3 and ground.
    • If less than 8 V 
    1. Ignition OFF/Vehicle OFF, disconnect the harness connector at the K9 Body Control Module.
    2. Test for infinite resistance between the signal circuit and ground
      • If less than infinite resistance, repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    3. Test for less than 2 Ω in the signal circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K9 Body Control Module.
    • Go to next step: If 8 V or greater 
  8. Ignition OFF/Vehicle OFF, disconnect the X3 harness connector at the K9 Body Control Module, ignition ON/vehicle in Service Mode.
  9. Test for less than 1 V between the S82 Windshield Wiper/Washer Switch signal circuit terminal 3 and ground.
    • If 1 V or greater 

      Repair the short to voltage on the circuit.

    • Go to next step: If less than 1 V 
  10. Test or replace the S82 Windshield Wiper/Washer Switch.

Windshield Wiper Motor Malfunction

  1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the M75 Windshield Wiper Motor. It may take up to 2 min for all vehicle systems to power down.
  2. Test for less than 10 Ω between the ground circuit terminal 4 and ground.
    • If 10 Ω or greater 
    1. Ignition OFF/Vehicle OFF.
    2. Test for less than 2 Ω in the ground circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, repair the open/high resistance in the ground connection.
    • Go to next step: If less than 10 Ω 
  3. Ignition ON/Vehicle in Service Mode.
  4. Verify the scan tool Windshield Wiper Park Switch parameter is Inactive.
    • If not Inactive 
    1. Ignition OFF/Vehicle OFF, disconnect the harness connector at the K9 Body Control Module.
    2. Test for infinite resistance between the signal circuit terminal 1 and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the K9 Body Control Module.
    • Go to next step: If Inactive 
  5. Install a 3 A fused jumper wire between the signal circuit terminal 1 and the ground circuit terminal 4.
  6. Verify the scan tool Windshield Wiper Park Switch parameter is Active.
    • If not Active 
    1. Ignition OFF/Vehicle OFF, remove the jumper wire, disconnect the harness connector at the K9 Body Control Module, ignition ON/vehicle in Service Mode.
    2. Test for less than 1 V between the signal circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • Go to next step: If less than 1 V
    3. Test for less than 2 Ω in the signal circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K9 Body Control Module.
    • Go to next step: If Active 
  7. Ignition OFF and all vehicle systems OFF, disconnect the KR12B Windshield Wiper Relay. It may take up to 2 min for all vehicle systems to power down.
  8. Test for less than 10 Ω between the ground circuit terminals listed below and ground.
    • terminal 85
    • terminal 87A
    • If 10 Ω or greater 
    1. Ignition OFF/Vehicle OFF.
    2. Test for less than 2 Ω in the ground circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, repair the open/high resistance in the ground connection.
    • Go to next step: If less than 10 Ω 
  9. Ignition ON/Vehicle in Service Mode.
  10. Verify a test lamp illuminates between the B+ circuit terminal 87 and the ground circuit terminal 87A.
    • If the test lamp does not illuminate and the circuit fuse is good 

      Replace the X50A Fuse Block - Underhood.

    • If the test lamp does not illuminate and the circuit fuse is open 
    1. Ignition OFF/Vehicle OFF, remove the test lamp. Disconnect the KR12C Windshield Wiper Speed Control Relay.
    2. Test for infinite resistance between the control circuits listed below and ground.
      • Terminal 87A
      • Terminal 87
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the M75 Windshield Wiper Motor
    • Go to next step: If the test lamp illuminates 
  11. Connect a test lamp between the control circuit terminal 86 and the ground circuit terminal 85.
  12. Verify the test lamp turns ON and OFF when commanding the Windshield Wiper Motor Relay Low and Off with a scan tool.
    • If the test lamp is always OFF 
    1. Ignition OFF/Vehicle OFF, remove the test lamp, disconnect the harness connector at the K9 Body Control Module.
    2. Test for infinite resistance between the control circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    3. Test for less than 2 Ω in the control circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K9 Body Control Module.
    • If the test lamp is always ON 
    1. Ignition OFF/Vehicle OFF, remove the test lamp, disconnect the harness connector at the K9 Body Control Module, ignition ON/vehicle in Service Mode.
    2. Test for less than 1 V between the control circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the K9 Body Control Module.
    • Go to next step: If the test lamp turns ON and OFF 
  13. Ignition OFF/Vehicle OFFF, connect the KR12B Windshield Wiper Relay and disconnect the KR12C Windshield Wiper Speed Control Relay, ignition ON/vehicle in Service Mode.
  14. Test for less than 10 Ω between the control circuit terminal 30 and ground.
    • If 10 Ω or greater 

      Test or replace the KR12B Windshield Wiper Relay.

    • Go to next step: If less than 10 Ω 
  15. Connect a test lamp between the control circuit terminal 30 and ground.
  16. Verify the test lamp turns ON and OFF when commanding the Windshield Wiper Motor Relay Low and Off with a scan tool.
    • If the test lamp does not turn ON and OFF 

      Test or replace the KR12B Windshield Wiper Relay.

    • Go to next step: If the test lamp turns ON and OFF 
  17. Verify a test lamp illuminates between the B+ circuit terminal 85 and ground.
    • If the test lamp does not illuminate 

      Replace the X50A Fuse Block - Underhood.

    • Go to next step: If the test lamp illuminates 
  18. Connect a test lamp between the B+ circuit terminal 85 and the control circuit terminal 86.
  19. Verify the test lamp turns ON and OFF when commanding the Windshield Wiper High Speed Relay High and Off with a scan tool.
    • If the test lamp is always OFF 
    1. Ignition OFF/Vehicle OFF, remove the test lamp, disconnect the harness connector at the K9 Body Control Module, ignition ON/vehicle in Service Mode.
    2. Test for less than 1 V between the control circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • Go to next step: If less than 1 V
    3. Ignition OFF/Vehicle OFF.
    4. Test for less than 2 Ω in the control circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K9 Body Control Module.
    • If the test lamp is always ON 
    1. Ignition OFF/Vehicle OFF, remove the test lamp, disconnect the harness connector at the K9 Body Control Module.
    2. Test for infinite resistance between the control circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the K9 Body Control Module.
    • Go to next step: If the test lamp turns ON and OFF 
  20. Ignition OFF/Vehicle OFF, connect the KR12C Windshield Wiper Speed Control Relay.
  21. Connect a test lamp between the M75 Windshield Wiper Motor control circuit terminal 5 and ground circuit terminal 4, ignition ON.
  22. Verify the test lamp turns ON and OFF when commanding the Windshield Wiper Motor Relay Low and Off with a scan tool.
    • If the test lamp is always OFF 
    1. Ignition OFF/Vehicle OFF, remove the test lamp, disconnect the KR12C Windshield Wiper Speed Control Relay.
    2. Test for infinite resistance between the control circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    3. Test for less than 2 Ω in the control circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, test or replace the KR12C Windshield Wiper Speed Control Relay.
    • If the test lamp is always ON 
    1. Ignition OFF/Vehicle OFF, remove the test lamp, disconnect the KR12C Windshield Wiper Speed Control Relay, ignition ON/vehicle in Service Mode.
    2. Test for less than 1 V between the control circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, test or replace the KR12C Windshield Wiper Speed Control Relay.
    • Go to next step: If the test lamp turns ON and OFF 
  23. Connect a test lamp between the M75 Windshield Wiper Motor control circuit terminal 3 and ground circuit terminal 4, ignition ON/vehicle in Service Mode.
  24. Verify the test lamp turns ON and OFF when commanding the Windshield Wiper High Speed Relay High and Off with a scan tool.
    • If the test lamp is always OFF 
    1. Ignition OFF/Vehicle OFF, remove the test lamp, disconnect the KR12C Windshield Wiper Speed Control Relay.
    2. Test for infinite resistance between the control circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    3. Test for less than 2 Ω in the control circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, test or replace the KR12C Windshield Wiper Speed Control Relay.
    • If the test lamp is always ON 
    1. Ignition OFF/Vehicle OFF, remove the test lamp, disconnect the KR12C Windshield Wiper Speed Control Relay, ignition ON/vehicle in Service Mode.
    2. Test for less than 1 V between the control circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, test or replace the KR12C Windshield Wiper Speed Control Relay.
    • Go to next step: If the test lamp turns ON and OFF 
  25. Test or replace the M75 Windshield Wiper Motor.
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