LEMON Manuals: Even more car manuals for everyone
Home >> GMC >> 2011 >> Terrain SLT, 2.4 C, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 178 (Lighting System) >> Diagnostic Information and Procedures >> Interior Backlighting Malfunction >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2010 GMC Terrain and 2010 Chevrolet Equinox. However, it is still accessible from the selected car via links, so may be relevant.

Dimmer Switch Malfunction

  1. Ignition OFF, disconnect the harness connector at the S36 instrument panel dimmer switch.
  2. Ignition OFF, test for less than 60 Ω between the low reference circuit terminal 10 and ground.
    • If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K9 BCM.
  3. Ignition ON, test for B+ between the B+ circuit terminal 5 and ground.
    • If less than the specified range, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 BCM.
    4. NOTE: The BCM will automatically put in a default Incandescent Dimming Duty Cycle Command setting of 50%. The next step will look for a brief change in the Incandescent Dimming Duty Cycle Command parameter from 50% to 5% - returning after 3 seconds to the 50% default setting.
  4. Install a 3 A fused jumper wire between the signal circuit terminal 9 and the B+ circuit terminal 5. Verify the scan tool Incandescent Dimming Duty Cycle Command briefly drops to 5%, returning after 3 seconds to the 50% default value.
    • If less than the specified range, test the signal circuit for 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 S36 instrument panel dimmer switch.

Interior Backlighting Malfunction

  1. Ignition OFF, disconnect the harness connector at the inoperative backlighting component.
  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 and ground.
  4. Command the LED Backlight Dimming Command 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, replace the inoperative backlighting component.
scientia non olet · About LEMON Manuals