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Circuit/System Testing

WARNING: This page is about a different car, the 2011 Buick Regal. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the harness connector at the S30 headlamp switch.
  2. Ignition ON, test for B+ between the control circuit terminal 1 and ground.
    • If less than the specified range, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 BCM.
    • If greater than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the K9 BCM.
  3. Verify the scan tool Incandescent Dimming Duty Cycle Command parameter is greater than 45%.
    • If less than the specified range, test the signal circuit terminal 12 for a short to voltage. If the circuit tests normal, replace the K9 BCM.
  4. Install a 3 A fused jumper wire between the signal circuit terminal 12 and the control circuit terminal 1. Verify the scan tool Incandescent Dimming Duty Cycle Command parameter is less than 8%
    • If greater than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 BCM.
  5. If all circuits test normal, test or replace the S30 headlamp switch.
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