GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2007 🢒 Lucerne 🢒 Diagnostic Navigation 🢒 Vehicle Diagnostic Information 🢒 Brake Warning Indicator Always On

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 signal 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

Data Communication Connector End Views

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.
    2. ⇒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.
    3. ⇒ 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.
    4. ⇒If 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