Important: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

The rear compartment lid can be released by operating the rear compartment lid release switch or by pressing the rear compartment lid release button on the remote keyless entry transmitter. The gear selector may be in any position, but the vehicle speed must equal 0 for the rear compartment lid to release.

When the ignition is ON, the body control module (BCM) supplies battery positive voltage to the rear compartment lid ajar switch through the rear compartment lid ajar switch signal circuit. When the rear compartment lid is opened, the signal circuit is connected to ground through the rear compartment lid ajar switch ground circuit and the voltage is pulled low within the BCM. In response, the BCM sends a low speed GMLAN serial data message to the driver information center (DIC) in the instrument panel cluster (IPC) to illuminate the rear compartment lid ajar indicator.

Schematic Reference

Body Rear End Schematics

Connector End View Reference

Body Rear End Connector End Views

Electrical Information Reference

Scan Tool Reference

With the ignition key ON, the rear compartment lid ajar indicator should illuminate when the rear compartment lid is opened and go off when the rear compartment lid is closed.

1. Ignition OFF, disconnect the C1 harness connector of the rear compartment lid latch.
2. Ignition OFF, test for less than 1.0 ohm of resistance between the rear compartment lid ajar switch ground circuit and ground.

⇒	If greater than 1.0 ohm, test the ground circuit for an open/high resistance.

3. Using a scan tool, verify the Trunk Ajar Switch parameter is Trunk Closed.

⇒	If not Trunk Closed, test the rear compartment lid ajar switch signal circuit for a short to ground. If the circuit tests normal, replace the BCM.

4. Install a 3-amp fused jumper wire between the signal circuit and ground. Verify the Trunk Ajar Switch parameter is Trunk Ajar.

⇒	If not Trunk Ajar, test the signal 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, test or replace the rear compartment lid latch.

1. Ignition OFF, disconnect the harness connector at the rear compartment lid latch.
2. Test for infinite resistance between the signal terminal and the ground terminal with the ajar switch in the open position.

⇒	If less than infinite resistance, replace the rear compartment lid latch.

3. Test for less than 3 ohms between the signal terminal and the ground terminal with the ajar switch in the closed position.

⇒	If greater than 3 ohms, replace the rear compartment lid latch.

4. Test for infinite resistance between each terminal and the rear compartment lid latch housing/case.

⇒	If less than infinite resistance, replace the rear compartment lid latch.

Important: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure.