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

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

Schematic Reference

Brake Warning System Schematics

Connector End View Reference

Computer/Integrating Systems Connector End Views

Electrical Information Reference

Scan Tool Reference

Scan Tool Data List

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 the Park Brake Switch parameter. Verify parameter is reading ON.

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

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

⇒	If short is found, repair the circuit.

4. Replace the BCM.

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