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Home >> Chevrolet >> 2011 >> Caprice >> Repair and Diagnosis >> External Pages >> Different car >> Section 18 (Lighting System) >> Diagnostic Information and Procedures >> High Intensity Discharge Lamp Malfunction >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2010 Chevrolet Camaro. However, it is still accessible from the selected car via links, so may be relevant.
WARNING: The high intensity discharge system produces high voltage and current. To reduce the risk of severe shocks and burns:
  • Never open the high intensity discharge system ballast or the arc tube assembly starter.
  • Never probe between the high intensity discharge system ballast output connector and the arc tube assembly.
  1. Ignition OFF, disconnect the KR49 low beam headlamp relay.
  2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 87 and ground.
    • If the test lamp illuminates, test the control circuit for a short to voltage.
  3. Verify that a test lamp illuminates between the B+ circuit terminal 30 and ground.
    • If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  4. Verify that a test lamp illuminates between the B+ circuit terminal 86 and ground.
    • If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
  5. Disconnect the harness connector at the appropriate T7 headlamp.
  6. Ignition OFF, scan tool OFF, exterior lamps OFF, test for less than 5.0 Ω between the ground circuit terminal A and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  7. Connect the harness connector at the appropriate T7 headlamp.
  8. Connect a 20 A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. Verify the high intensity discharge headlamps are activated.
    • If the high intensity discharge headlamps do not activate and the circuit fuse is good, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the T7 headlamp.
    • If the high intensity discharge headlamps do not activate and the circuit fuse is open, test the control circuit for a short to ground. If the circuit tests normal, test or replace the T7 headlamp.
  9. Connect a test lamp between the B+ circuit terminal 86 and the control circuit terminal 85.
  10. Command the Headlamp Low Beam 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 ON, test the control circuit for a short to ground. If the circuit tests normal, replace the K9 BCM.
    • If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K9 BCM.
  11. If all circuits test normal, replace the KR49 low beam headlamp relay.
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