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Home >> GMC >> 2011 >> Acadia SL, AWD >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Interior/Illumination Lights >> Lighting System >> Diagnostic Information and Procedures >> Interior Backlighting Malfunction >> Circuit/System Testing

Circuit/System Testing

Dimmer Switch Malfunction

  1. Ignition OFF, disconnect the harness connector at the headlamp switch.
  2. Ignition OFF, verify that a test lamp illuminates between the ground circuit terminal 8 and B+.
    • If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  3. Ignition ON, test for 11.8-12.2 V between the 12 V reference circuit terminal 15 and ground.
    • If greater than the specified range, test the 12 V reference circuit for a short to voltage. If the circuit tests normal, replace the BCM.
    • If less than the specified range, test the 12 V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  4. Ignition ON, verify the scan tool Dimming Control Signal parameter is less than 0.1 V.
    • If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the BCM.
  5. Install a 3 A fused jumper wire between the signal circuit terminal 13 and the voltage reference circuit terminal 15. Verify the scan tool Dimming Control Signal parameter is greater than 11.7 V.
    • If less 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 BCM.
  6. If all circuits test normal, test or replace the headlamp switch.

Interior Backlighting Malfunction

    NOTE:

    Each back lighted component may need to be disconnected to isolate a short to voltage or short to ground. Use the schematic to identify the following:

    • Back lighted components the vehicle is equipped with.
    • Component locations on the back lighting dimming control circuit
    • Each component's control and ground circuit terminals
  1. Ignition OFF, disconnect the harness connector at any component with inoperative backlighting.
  2. Ignition OFF, scan tool disconnected, interior lamps OFF, doors CLOSED, test for less than 5 Ω between the ground circuit and ground.
    • If greater than the specified value, test the ground circuit for an open/high resistance.
  3. Connect a test lamp between the control circuit terminal and ground.
  4. Command the Incandescent Dimming or LED Dimming ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
    • If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
    • If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, test or replace the component with the inoperative backlighting.
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