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Home >> GMC >> 2006 >> Sierra 1500 HD, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1104 (Door Lock Systems & Door Handles) >> Diagnostic Information and Procedures >> Trunk Release Inoperative >> Circuit/System Testing >> Trunk Release Malfunction

Trunk Release 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 trunk release relay.
  2. Ignition OFF, test for less than 5.0 ohms between the relay coil ground circuit terminal 85 and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 30 and ground.
    • If the test lamp illuminates, test the control circuit for a short to voltage.
  4. Verify that a test lamp illuminates between the relay switch B+ circuit terminal 87 and ground.
    • If the test lamp does not illuminate, test the relay switch B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the relay switch B+ circuit fuse is open, test the relay controlled output circuit terminal 30 for a short to ground.
  5. Ignition OFF, disconnect the harness connector at the rear compartment lid latch.
  6. Ignition OFF, test for less than 5.0 ohms between the ground circuit terminal B and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  7. Connect the harness connector at the rear compartment lid latch.
  8. Ignition ON, connect a 15A fused jumper wire between the B+ circuit terminal 87 and the control circuit terminal 30. Verify the rear compartment lid release actuator is activated.
    • If the rear compartment lid release actuator does not activate, test the control circuit terminal 30 for an open/high resistance. If the circuit tests normal, test or replace the rear compartment lid latch.
  9. Ignition OFF, connect a test lamp between the relay control circuit terminal 86 and the relay coil ground circuit terminal 85.
  10. Command the trunk release relay 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.
  11. If all circuits test normal, test or replace the trunk release relay.
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