For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category.

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Liftgate Relay B+ | 2 | 2 | -- | --
Liftgate Release Switch Signal | B3265 00 | 1 | -- | --
Liftgate Relay High Control | B2495 02 | B2495 01 | B2495 01 | --
Liftgate Relay Low Control | -- | B2495 01 | B2495 01 | --
Liftgate Latch Control | 2 | 2 | 2 | --
Liftgate Release Switch Ground | -- | 1 | -- | --
Liftgate Latch Ground | -- | 2 | -- | --
1.Liftgate Release Switch Inoperative 2. Liftgate Latch Inoperative

### Circuit/System Description

The liftgate switch is an input to the body control module (BCM). The BCM supplies battery voltage to the signal circuit and when the liftgate switch is activated the signal circuit voltage goes low. The BCM controls the liftgate release actuator assembly through the LIFTGATE relay. When the liftgate switch signal is activated, the BCM enables the LIFTGATE relay by applying battery voltage to the liftgate relay circuit and the relay is energized when the BCM grounds the LIFTGATE relay control circuit. When the relay is energized battery voltage is supplied to the liftgate release actuator assembly through the liftgate release actuator control circuit.

### Reference Information

#### Schematic Reference

Liftgate Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Verification

1. Ignition ON, observe the scan tool Int. Trunk/Liftglass Sw. parameter while pressing and releasing the liftgtate release switch. The reading should change between Active and Inactive.

⇒ | If not the specified value, refer to Liftgate Release Switch Circuit Test.

2. Liftgate closed and unlocked, perss and release the liftgate release switch. The liftgate latch should release.

⇒ | If the liftgate latch does not release, refer to Liftgate Actuator Circuit Test.

### Circuit/System Testing

#### Liftgate Release Switch Circuit Test

1. Ignition OFF, disconnect the harness connector at the liftgate release switch.
2. 2. Test for less than 10 ohms between the ground circuit terminal 1 and ground.
3. Ignition ON, verify the scan tool Trunk/Liftglass Sw. parameter is Inactive.

⇒ | If not the specified value, test the signal circuit terminal 2 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 2 and the ground circuit terminal 1. Verify the scan tool Trunk/Liftglass 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.

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

#### Liftgate Actuator Circuit Test

1. Ignition OFF, disconnect the rear closure relay.
2. Ignition ON, verify that a test lamp does not illuminate between the release actuator control circuit terminal 87 and ground.

⇒ | If the test lamp illuminates, test the control circuit for a short to voltage.

3. Verify that a test lamp illuminates between the B+ circuit terminal 30 and ground.

⇒ | If the test lamp does not illuminate, replace the underhood fuse block.

4. Ignition OFF, disconnect the harness connector at the liftgate release actuator.
5. Test for less than 5.0 ohms between the ground circuit terminal 3 and ground.

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

6. Connect the harness connector at the liftgate release actuator.
7. Briefly connect a 15A fused jumper wire between the B+ circuit terminal 30 and the release actuator control circuit terminal 87. Verify the liftgate release actuator activates.

⇒ | If the liftgate release actuator does not activate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the liftgate release actuator.

8. Connect a test lamp between the relay high control circuit terminal 85 and the relay low control circuit terminal 86.
9. Press and release the liftgate release switch. The test lamp should turn ON and OFF when changing between the commanded states.

⇒ | If the test lamp is always OFF, test the control circuits for a short to ground or an open/high resistance. If the circuits test normal, replace the BCM.

10. If all circuits test normal, test or replace the rear closure relay.

### Component Testing

#### Relay Test

1. Ignition OFF, disconnect the front fog lamp relay.
2. Test for 70-100 ohms between terminals 85 and 86.

⇒ | If the resistance is not within the specified range, replace the relay.

3. Test for infinite resistance between the following terminals:

• | 30 and 85

• | 30 and 86

• | 30 and 87

• | 85 and 87

⇒ | If not the specified value, replace the relay.

4. Install a 10A fused jumper wire between relay terminal 85 and B+. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 ohms between terminals 30 and 87.

⇒ | If greater than the specified range, replace the relay.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Liftgate Outside Handle Replacement

• | Liftgate Latch Replacement

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