FixVault

Circuit/System Testing

WARNING: This page is about a different car, the 2007 Cadillac XLR. However, it is still accessible from the selected car via links, so may be relevant.

Interior Backlighting Malfunction

  1. Ignition ON, install a scan tool and observe the park lamps signal parameter in the IPC data list while turning the parks lamps ON and OFF. The reading should change between OFF and ON.
    • If the parameter is always ON, test the park lamp supply voltage circuit at connector C1 terminal A16 for a short to voltage. If the circuit tests normal, replace the IPC.
    • If the parameter is always OFF, test the park lamp supply voltage circuit at connector C1 terminal A16 for a short to ground or and open/high resistance. If the circuit tests normal, replace the IPC.
  2. Ignition OFF, disconnect the harness connector at the component with the inoperative backlighting.
  3. Test for less than 1 ohm of resistance between the ground circuit and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  4. Connect a test lamp between the backlight lamp control circuit and ground.
  5. Command the park lamps ON and OFF with the park lamps switch. 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 control module associated with the inoperative backlight.
    • If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the control module associated with the inoperative backlight.
  6. If all circuits test normal, test or replace the component with the inoperative backlighting.

Dimmer Switch Malfunction

  1. Ignition OFF, disconnect the harness connector at the dimmer/head up display (HUD) switch.
  2. Test for less than 1 ohm of resistance between the ground circuit terminal 1 and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance. If the circuit tests normal, replace the IPC.
  3. Ignition ON, verify the scan tool dim select switch parameter is INACTIVE.
    • If not the specified value, test the signal circuit terminal 4 for a short to ground. If the circuit tests normal, replace the IPC.
  4. Install a 3A fused jumper wire between the signal circuit terminal 4 and ground. Verify the scan tool dim select switch parameter is ACTIVE.
    • If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPC.
  5. Verify the scan tool dim down switch parameter is INACTIVE.
    • If not the specified value, test the signal circuit terminal 3 for a short to ground. If the circuit tests normal, replace the IPC.
  6. Install a 3A fused jumper wire between the signal circuit terminal 3 and ground. Verify the scan tool dim down switch parameter is ACTIVE.
    • If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPC.
  7. Verify the scan tool dim up switch parameter is INACTIVE.
    • If not the specified value, test the signal circuit terminal 2 for a short to ground. If the circuit tests normal, replace the IPC.
  8. Install a 3A fused jumper wire between the signal circuit terminal 2 and ground. Verify the scan tool dim up switch parameter is ACTIVE.
    • If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPC.
  9. If all circuits test normal, test or replace the dimmer/head up display (HUD) switch.