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Home › Chevrolet › 2012 › Traverse LS, AWD › Repair and Diagnosis › Accessories & Equipment › Headlights › Lighting System › Diagnostic Information and Procedures › DTC B2575 › Circuit/System Testing

Circuit/System Testing

  1. Ignition OFF, disconnect the headlamps low beam 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 85 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 30 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 headlamp - low beam.
  6. Test for less than 5 Ω between the ground circuit terminal listed below and ground:
    • RPO WDA/X88 - terminal A
    • RPO Z88 - terminal B
    • RPO W49/TVD - terminal 6
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  7. Connect the harness connector at the headlamp - low beam.
  8. Connect a 10 A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. Verify the headlamp - low beam is activated.
    • If the headlamp - low beam does 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 headlamp - low beam.
    • If the headlamp - low beam does 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 headlamp - low beam.
  9. Connect a test lamp between the B+ circuit terminal 85 and the control circuit terminal 86.
  10. Command the Low Beams 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 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 BCM.
  11. If all circuits test normal, test or replace the headlamps low beam relay.
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