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Home >> Hummer >> 2008 >> H3 Base, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 88 (Lighting Systems) >> Diagnostic Information and Procedures >> DTC B2575 >> Circuit/System Testing
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Circuit/System Testing

WARNING: This page is about a different car, the 2008 Chevrolet Malibu Classic. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the LO/BEAM relay.
  2. Ignition ON, verify that a test lamp illuminates between the B+ circuit of the LO/BEAM relay and ground.
    • If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  3. Connect a test lamp between the B+ circuit of the LO/BEAM relay and the control circuit of the LO/BEAM relay.
  4. Command the backup lamps 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.
  5. If all circuits test normal, replace the LO/BEAM relay.
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