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Home >> Cadillac >> 2007 >> Escalade EXT >> Repair and Diagnosis >> External Pages >> Different car >> Section 910 (Lighting Systems) >> Diagnostic Information and Procedures >> DTC B3884 >> Circuit/System Testing
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Circuit/System Testing

WARNING: This page is about a different car, the 2007 GMC Sierra and 2007 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the X5 harness connector at the underhood fuse block.
  2. Connect a test lamp between the CHMSL relay control circuit terminal K6 and ground at the harness connector.
  3. Apply the brake pedal ON and OFF. 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 voltage. If the circuit tests normal, replace the BCM.
    • 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.
  4. If all circuits test normal, test or replace the underhood fuse block.
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