LEMON Manuals: Even more car manuals for everyone
Home >> GMC >> 2006 >> Sierra 1500 HD, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1087 (Lighting Systems) >> Diagnostic Information and Procedures >> Headlamps Malfunction >> Circuit/System Testing >> Headlamp Switch Malfunction

Headlamp Switch Malfunction

WARNING: This page is about a different car, the 2008 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the X1 and X2 harness connectors at the turn signal/multifunction switch.
  2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal 9.
    • If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  3. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal 8.
    • If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  4. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal 1.
    • If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  5. Ignition ON, verify the scan tool headlamp switch parameter is INACTIVE.
    • If not the specified value, test the signal circuits at terminal 4 and terminal 5 for shorts to ground. If the circuits test normal, replace the BCM.
  6. Verify the scan tool flash to pass switch parameter is INACTIVE.
    • If not the specified value, test the signal circuit terminal 10 for a short to ground. If the circuit tests normal, replace the BCM.
  7. Verify the scan tool high beam select switch parameter is INACTIVE.
    • If not the specified value, test the signal circuit terminal 7 for a short to ground. If the circuit tests normal, replace the BCM.
  8. Install a 3A fused jumper wire between the signal circuit terminal 5 and ground. Verify the scan tool headlamp switch parameter is ACTIVE.
    • If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  9. Install a 3A fused jumper wire between the signal circuit terminal 4 and ground. Verify the scan tool headlamp switch parameter is ACTIVE.
    • If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  10. Install a 3A fused jumper wire between the signal circuit terminal 10 and ground. Verify the scan tool flash to pass switch parameter is ACTIVE.
    • If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  11. Install a 3A fused jumper wire between the signal circuit terminal 7 and ground. Verify the scan tool high beam select switch parameter is ACTIVE.
    • If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  12. If all circuits test normal, test or replace the turn signal/multifunction switch.
scientia non olet · About LEMON Manuals