Liftgate Ajar Indicator Malfunction

Liftgate Ajar Indicator Malfunction

Diagnostic Instructions

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

Diagnostic Fault Information





Circuit/System Description

The BCM receives a discrete input from 2 ajar switches to indicate the status of the liftgate. The liftgate ajar switches are normally open when the liftgate is fully closed. When the liftgate is opened, the ajar switch contacts close providing a path to ground. The instrument panel cluster (IPC) receives a serial data message from the BCM indicating the liftgate ajar status and the driver information center (DIC) located at the bottom of the IPC, illuminates the rear access open message.

Reference Information
Schematic Reference

Release Systems Schematics (Release Systems Schematics)
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, observe the scan tool Rear Closure Ajar Sw. parameter while opening and closing the liftgate. The parameter should change between Active and Inactive.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the rear window wiper control module.
2. Disconnect the harness connectors at the left and right liftgate ajar switches.
3. Test for less than 1 ohm between the ground circuit terminal A and ground.

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

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

• If not the specified value, test the left and right signal circuit terminal B for a short to ground. If the circuits test normal, replace the BCM.

5. Install a 3A fused jumper wire between the left signal circuit terminal B and ground. Verify the scan tool Rear Closure Ajar Sw. 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.

6. Install a 3A fused jumper wire between the right signal circuit terminal B and ground. Verify the scan tool Rear Closure Ajar Sw. parameter is Active.

• If not the specified value, test the signal circuit for a short to voltage or an open/high resistance.

7. Ignition OFF, connect the harness connector at the right liftgate ajar switch.
8. Ignition ON, observe the scan tool Rear Closure Ajar Sw. parameter while opening and closing the liftgate. The parameter should change between Active and Inactive.

• If the parameter does not change, test or replace the right liftgate ajar switch.

9. Ignition OFF, connect the harness connector at the rear window wiper control module.
10. Ignition ON, observe the scan tool Rear Closure Ajar Sw. parameter while opening and closing the liftgate. The parameter should change between Active and Inactive.

• If the parameter does not change, replace the rear window wiper control module.

11. If all circuits test normal, test or replace the left liftgate ajar switch.

Component Testing

1. Ignition OFF, disconnect the harness connector at the appropriate liftgate ajar switch.
2. Test for infinite resistance between the signal terminal B and the ground terminal A with the switch in the open position.

• If not the specified value, replace the liftgate ajar switch.

3. Test for less than 2 ohms between the signal terminal B and the ground terminal A with the switch in the closed position.

• If greater than the specified range, replace the liftgate ajar switch.

Repair Instructions

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

Control Module References (Programming and Relearning) for BCM or IPC replacement, programming, and setup.