Trunk Ajar Indicator Malfunction

Trunk Ajar Indicator Malfunction

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provide an overview of each diagnostic category.



Circuit/System Description

The body control module (BCM) receives an input from the rear compartment lid ajar switch. The ajar switch is normally open when the trunk is fully closed. When the trunk is opened, the ajar switch contacts close providing a path to ground. The driver information center (DIC) located at the bottom of the instrument panel cluster (IPC), illuminates the rear access open message when the trunk is open. The IPC receives a GMLAN serial data message from the BCM indicating the trunk ajar status. If this message is displayed and the vehicle speed is greater than 8.1 km/h (5 mph), a chime will sound.


Reference Information
Schematic Reference

Release Systems Schematics (Release Systems Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Door Ajar Indicator Description and Operation (Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning) for Scan Tool Information


Circuit/System Verification

Ignition ON, verify that the scan tool Rear Closure Ajar parameter changes between Active and Inactive, while opening and closing the trunk.


Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the rear compartment lid latch.
2. Test for less than 1 ohm of resistance between the ground circuit terminal 3 and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, verify the scan tool Rear Closure Ajar parameter is Inactive.

• If not the specified value, test the signal circuit for a short to ground. If the circuit tests normal, replace the BCM.

4. Install a 3A fused jumper wire between the signal circuit terminal 1 and ground. Verify the scan tool Rear Closure Ajar 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.

5. If all circuits test normal, test or replace the rear compartment ajar indicator switch.



Component Testing

1. Ignition OFF, disconnect the harness connector at the rear compartment lid latch.
2. Test for infinite resistance between the signal terminal 1 and the ground terminal 3 with the switch in the open position.

• If not the specified value, replace the rear compartment ajar indicator switch.

3. Test for less than 1.0 ohms between the signal terminal 1 and the ground terminal 3 with the switch in the closed position.

• If greater than the specified range, replace the rear compartment ajar indicator switch.




Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Rear Compartment Lid Ajar Indicator Switch Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for BCM replacement, setup, and programming