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Home >> GMC >> 2006 >> Sierra 1500 HD, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1293 (Lighting Systems) >> Diagnostic Information and Procedures >> Turn Signal Lamps and/or Indicators Malfunction >> Circuit/System Testing >> Turn Signal Lamps Malfunction

Turn Signal Lamps Malfunction

WARNING: This page is about a different car, the 2009 GMC Sierra, 2009 GMC Cab & Chassis Sierra, 2009 Chevrolet Silverado, and 2009 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the X4 harness connector at the BCM.
  2. Verify that a test lamp illuminates between the B+ circuit terminal 1 and ground.
    • If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  3. Verify that a test lamp illuminates between the B+ circuit terminal 2 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 3 and ground.
    • If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  5. Ignition OFF, connect the X4 harness connector at the BCM.
  6. Ignition OFF, disconnect the harness connector at the inoperative turn signal lamp.
  7. Ignition OFF, exterior lamps OFF, test for less than 5 ohms between the ground circuit terminal GRD and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  8. Connect a test lamp between the control circuit terminal MJR and ground.
  9. Command the appropriate turn signal lamp 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 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.
  10. If all circuits test normal, replace the appropriate turn signal lamp.