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.

### Circuit/System Description

The body control module (BCM) sees the park brake switch and brake fluid level switch input to grounded, it sends a serial data message to the instrument panel cluster (IPC) requesting illumination of the red brake indicator.

### Reference Information

#### Schematic Reference

Hydraulic Brake Schematics

#### Connector End View Reference

Hydraulic Brake Connector End Views

#### Description and Operation

Brake Warning System Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Scan Tool Data List

### Circuit/System Testing

1. With the scan tool, select instrument panel special functions Lamp Test. Command the instrument panel lamps OFF. Verify brake lamp turns OFF.

⇒ | If the brake lamp does not turn OFF, replace the IPC.

2. Disconnect the park brake switch, with a scan tool observe park brake switch parameter. Verify parameter is reading ON.

⇒ | If parameter is OFF, replace the park brake switch.

3. Test the signal circuit of the park brake switch for a short to ground. Verify no short is found.

⇒ | If a short is found, repair the circuit.

4. Replace the BCM.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Parking Brake Indicator Switch Replacement

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