For 1990-2009 cars

### Diagnostic Instructions

• | Perform the prior to Diagnostic System Check - Vehicle 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.

### DTC Descriptor

DTC B3618 00: Exterior Liftgate Unlatch Switch Circuit

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Rear Compartment Lid Exterior Release Switch Signal | B3618 00 | 2 | B3618 00 | --
Rear Compartment Lid Exterior Release Switch Ground | -- | B3618 00 | B3618 00 | --
1. Trunk Release Malfunction 2. Trunk Release Exterior Switch Malfunction

### Circuit/System Description

The exterior rear compartment lid release switch receives a signal from the body control module (BCM). When the exterior rear compartment lid release switch is activated the signal circuit is pulled to ground. The BCM applies battery positive voltage to the trunk release relay control circuit which energizes the relay. The trunk release relay is grounded at all times. With the relay coil energized, the relay switch contacts close allowing battery voltage to flow to the rear compartment lid release actuator causing the rear compartment lid to release.

### Conditions for Running the DTC

Battery voltage must be between 9-16 V.

### Conditions for Setting the DTC

The BCM detects a fault in the exterior trunk release switch signal circuit.

### Action Taken When the DTC Sets

The rear compartment latch will not operate.

### Conditions for Clearing the DTC

• | This DTC will be current for as long as the fault is present.

• | When the fault is no longer present, the DTC will be a history DTC.

• | A history DTC will clear after 50 ignition cycles.

### 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

Command the trunk release by using the exterior rear compartment lid release switch. The rear compartment lid release actuator should release the trunk lid.

### Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the S58A Rear Compartment Lid Release Switch - Exterior.
2. Connect a 3 A jumper between the rear compartment lid exterior release switch signal terminal 1 and ground. The rear compartment lid actuator should click.

⇒ | If the rear compartment lid actuator does not click, test the rear compartment lid exterior release switch signal for an open/high resistance.

3. Test for less than 1 Ω between the ground circuit terminal 3 and ground.

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

4. If all circuits test normal, test or replace the S58A Rear Compartment Lid Release Switch - Exterior.

### Component Testing

1. Ignition OFF, disconnect the harness connector at the S58A Rear Compartment Lid Release Switch - Exterior.
2. Test for infinite resistance between the signal terminal 1 and the ground terminal 3 with the switch in the open position

⇒ | If not within the specified range, replace the S58A Rear Compartment Lid Release Switch - Exterior.

3. Test for less than 2 Ω between the signal terminal 1 and the ground terminal 3 with the switch in the closed position.

⇒ | If less than the specified value, replace the S58A Rear Compartment Lid Release Switch - Exterior.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Rear Compartment Lid Release Switch Replacement

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