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
--- | --- | --- | --- | ---
Rear End Release Relay B+ | 1 | 1 | -- | --
Trunk Release Switch Signal | B2730 00 | 2 | 2 | --
Rear Compartment Lid Latch Control | 1 | 1 | 1 | --
Rear End Release Relay Control | B3265 00 | B3265 00 | B3265 00 | --
Rear Compartment Lid Latch Ground | -- | 1 | 1 | --
Rear Compartment Lid Release Switch Ground | -- | 2 | 2 | --
1. Trunk release is inoperative from both the switch and keyless entry transmitter 2. Trunk release is inoperative only from switch

### Circuit/System Description

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 must be in Park for the trunk to release.

The body control module (BCM) monitors the signal circuit to the rear compartment lid release switch. When the rear compartment lid release switch is pressed, the trunk release signal is pulled low within the BCM. In response, the BCM applies ground to the trunk relay control circuit, which energizes the coil side of the trunk relay. The switch side of the trunk relay then closes, supplying battery positive voltage through the relay and the control circuit to the rear compartment lid latch. The rear compartment lid latch, then releases the rear compartment lid so that it may be manually raised to an open position.

### Reference Information

#### Schematic Reference

Release Systems Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Luggage Compartment 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 Trunk Switch parameter while pressing the rear compartment lid release switch. The parameter should change between Active and Inactive.

⇒ | If the value does not change, refer to Trunk Release Switch Malfunction.

2. Command the Trunk Release Test with a scan tool, the rear compartment lid latch should release the trunk lid.

⇒ | If the rear compartment lid latch does not release, refer to Rear Compartment Lid Latch Malfunction.

### Circuit/System Testing

#### Trunk Release Switch Malfunction

1. Ignition OFF, disconnect the harness connector at the rear compartment lid release switch.
2. Test for less than 1 Ω between the ground circuit terminal 5 and ground.

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

3. Ignition ON, verify the scan tool Trunk Switch parameter is Inactive.

⇒ | If not the specified value, test the signal circuit terminal 13 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 A and the ground circuit terminal B. Verify the scan tool Trunk Switch 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 lid release switch.

#### Rear Compartment Lid Latch Malfunction

1. Ignition OFF, disconnect the Rear End Release relay.
2. Ignition ON, verify that a test lamp does not illuminate between the 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 85 and ground.

⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuit terminal 87 for a short to ground. If the circuit tests normal, test or replace the Rear End Release relay.

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

⇒ | If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.

5. Ignition OFF, disconnect the harness connector at the rear compartment lid latch.
6. Test for less than 1 Ω between the ground circuit terminal 4 and ground.

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

7. Connect the harness connector at the rear compartment lid latch.
8. Ignition ON, connect a 10A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. Verify the rear compartment lid latch is activated.

⇒ | If the rear compartment lid latch does not activate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the rear compartment lid latch.

9. Connect a test lamp between the B+ circuit terminal 85 and the control circuit terminal 86.
10. Command the Trunk Release Test ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

⇒ | If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM.

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

11. If all circuits test normal, test or replace the Rear End Release relay.

### Component Testing

#### Rear Compartment Lid Latch

1. Ignition OFF, disconnect the harness connector at the rear compartment lid latch.
2. Install a 10A fused jumper wire between the control terminal 3 and 12V. Install a jumper wire between the ground terminal 4 and ground. Verify the rear compartment lid latch activates.

⇒ | If the latch does not perform as specified, replace the rear compartment lid latch.

#### Rear Compartment Lid Release Switch

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

⇒ | If not the specified value, replace the rear compartment lid release switch

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

⇒ | If greater than the specified range, replace the rear compartment lid release switch.

4. Test for infinite resistance between each terminal and the lid release switch housing/case.

⇒ | If not the specified value, replace the rear compartment lid release switch.

#### Relay Test

1. Ignition OFF, disconnect the Rear End Release relay.
2. Test for 65-90 Ω between terminals 85 and 86.

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

3. Test for infinite resistance between the following terminals:

• | 30 and 86

• | 30 and 87

• | 30 and 85

• | 85 and 87

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

4. Install a 10A fused jumper wire between relay terminal 85 and 12V. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 Ω 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.

• | Rear Compartment Lid Latch Replacement

• | Relay Replacement

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