For 1990-2009 cars

### Diagnostic Fault Information

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

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Liftgate Ajar Signal Circuit | 1 | 2 | -- | --
Liftgate Ajar Ground Circuit | -- | 2 | 2 | --
Body Control Module | 2 | 2 | 1 | --
Instrument Panel Cluster | 1, 2 | 2 | 1, 2 | --
1. Liftgate Ajar Light Stays On 2. Liftgate Ajar Light Will not Come On

### Circuit/System Description

With the rear hatch/gate door closed the rear hatch door ajar light is off. When the rear hatch is opened or a door is not closed tightly the rear door ajar light will turn on in the instrument panel cluster (IPC)

### Diagnostic Aids

The door ajar switches supply a ground to the body control module (BCM) when the door is open. Once the door is closed the door ajar switch opens canceling the ground to the BCM. The BCM sends a signal to the IPC to turn on the door ajar light when a door is open.

### Reference Information

#### Schematic Reference

Door Lock/Indicator Schematics

#### Connector End View Reference

Vehicle Access Connector End Views

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

### Circuit/System Verification

Ignition ON, observe the scan tool rear door ajar switch parameter while opening and closing the rear hatch. The reading should change between low and high.

### Circuit/System Testing

#### Rear Hatch Ajar Switch Circuit Testing

1. Ignition OFF, disconnect the harness connector at the rear hatch ajar switch.
2. Test for less than 1.0 ohm of resistance between the ground circuit and ground.

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

3. Verify the scan tool liftgate ajar switch parameter is low.

⇒ | If not low, test the signal circuit for a short to ground. If the circuit tests normal, replace the BCM.

⇒ | If the rear hatch indicator is still ON, test the IPC rear hatch indicator signal circuit for a short to voltage. If the circuit tests normal, replace the IPC

4. Install a 3-amp fused jumper wire between the signal circuit and ground. Verify the scan tool door ajar parameter is high.

⇒ | If not high, test the signal circuit of the door ajar switch for a short to voltage or an open/high resistance. If circuit tests normal, replace the BCM.

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

### Component Testing

#### Door Ajar Switch Testing

1. Ignition OFF, disconnect the harness connector at the rear hatch ajar switch.
2. Test for infinite resistance between the signal terminal and the voltage supply terminal with the switch in the open position.

⇒ | If less than infinite resistance, replace the door ajar switch.

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

⇒ | If greater than 1.0 ohms, replace the rear hatch ajar switch.

### Repair Instructions

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

• | 11687

• | Control Module References for IPC and BCM replacement, setup, and programming