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Home >> GMC >> 2019 >> Terrain SL >> Repair and Diagnosis >> External Pages >> Different car >> Section 76 (Wiper System And Washer System) >> Diagnostic Information And Procedures >> DTC B370B: Rear Wiper Function Control Circuit >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2018 GMC Terrain and 2018 Chevrolet Equinox. However, it is still accessible from the selected car via links, so may be relevant.
  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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