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Home >> Buick >> 2021 >> Envision Preferred, AWD >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Wiper/Washer Systems >> Wiper System And Washer System >> Diagnostic Information and Procedures >> DTC B12FA >> Circuit/System Testing

Circuit/System Testing

  1. Ignition OFF and all vehicle systems OFF, disconnect the X1 connector at the X50A Fuse Block - Underhood. It may take up to 2 min for all vehicle systems to power down.
  2. Verify a test lamp illuminates between the ground circuit terminal A2 and B+.
    • If the test lamp does not illuminate 

      Repair the open/high resistance on circuit 750 or ground connection.

    • Go to next step: If the test lamp illuminates 
  3. Ignition ON.
  4. Connect a test lamp between control circuit terminal C1 and ground circuit terminal A2.
  5. Verify the test lamp turns on and off when commanding the Windshield Washer Pump On and Off with the scan tool.
    • If the test lamp is always on 
    1. Test circuit 2268 for a short to voltage.
      • If a short to voltage is found, repair the fault on the circuit.
      • Go to next step: If a short to voltage is not found.
    2. Replace the K219 Lighting Control Module.
    • Go to next step: If the test lamp is always off 
    1. Test circuit 2268 for a short to ground.
      • If a short to ground is found, repair the fault on the circuit.
      • Go to next step: If a short to ground is not found.
    2. Test circuit 2268 for an open/high resistance.
      • If an open/high resistance is found, repair the fault on the circuit.
      • Go to next step: If an open/high resistance is not found.
    3. Replace the K219 Lighting Control Module.
    • Go to next step: If the test lamp turns on and off 
  6. Replace the X50A Engine Wiring Harness Junction Block.
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