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Home >> GMC >> 2018 >> Terrain SL >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Wiper/Washer Systems >> Wiper System And Washer System >> Diagnostic Information And Procedures >> DTC B370B: Rear Wiper Function Control Circuit >> Circuit/System Testing
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Circuit/System Testing

  1. Ignition OFF, disconnect the X4 harness connector at the K9 Body Control Module, ignition ON.
  2. Verify the M45 Rear Wiper Motor is not activated.
    • If the M45 Rear Wiper Motor is activated 
    1. Ignition OFF, disconnect the X1 harness connector at the X50A Fuse Block - Underhood, ignition ON.
    2. Test for less than 1 V between the control circuit terminal 16 and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the X50A Fuse Block - Underhood.
    • Go to next step: If the M45 Rear Wiper Motor is not activated 
  3. Connect a 10 A fused jumper wire between the control circuit terminal 10 and B+.
  4. Verify the M45 Rear Wiper Motor activates.
    • If the M45 Rear Wiper Motor does not activate 
    1. Ignition OFF, remove the jumper wire, disconnect the X1 harness connector at the X50A Fuse Block - Underhood.
    2. Test for infinite resistance between the control circuit terminal 16 and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • 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 X50A Fuse Block - Underhood.
    • Go to next step: If the M45 Rear Wiper Motor activates 
  5. Test or replace the K9 Body Control Module.
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