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Home >> Hummer >> 2008 >> H3 Alpha >> Repair and Diagnosis >> External Pages >> Different car >> Section 101 (Lighting Systems) >> Diagnostic Information and Procedures >> Interior Backlighting Malfunction >> Circuit/System Testing
July 1: So it begins. Don't worry, this is not in the correct legal jurisdiction!

Circuit/System Testing

WARNING: This page is about a different car, the 2008 Chevrolet Malibu Classic. However, it is still accessible from the selected car via links, so may be relevant.

Interior Backlighting Inoperative

  1. Ignition OFF, disconnect the harness connector at the dimmer switch.
  2. Install a 3A fused jumper wire between the signal circuit terminal C and ground.
  3. Ignition ON, headlamp switch in the PARK position. The interior backlighting should illuminate.
    • If the interior backlighting does not illuminate, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  4. Install a 3A fused jumper wire between the signal circuit terminal C and the low reference circuit terminal D. The interior backlighting should illuminate.
    • If the interior backlighting does not illuminate, test the low reference circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, replace the dimmer switch.

Interior Backlighting Does Not Dim

  1. Ignition OFF, disconnect the dimmer switch.
  2. Ignition ON, headlamp switch in the PARK position. The interior backlighting should not illuminate.
    • If the interior backlighting illuminates, test the signal circuit terminal C for a short to ground. If the circuit tests normal, replace the BCM.
  3. If all circuits test normal, replace the dimmer switch.