Brake Warning Light Always On (Without Audible Brake Warning)
- Disconnect park brake warning switch connector. Turn ignition on. Release parking brake. If warning light remains on, go to next step. If warning light turns off, check park brake warning switch adjustment. If adjustment is okay, replace park brake warning switch.
- Disconnect brake pressure warning switch connector. If warning light remains on, go to next step. If warning light turns off, diagnose hydraulic brake system. See appropriate
DISC & DRUM article in BRAKES.
- Locate Electronic Brake Control Module (EBCM) near brake master cylinder. Disconnect EBCM 10-pin connector. If warning light remains on, go to next step. If warning light turns off, diagnose Anti-Lock Brake System (ABS). See appropriate
ANTI-LOCK article in BRAKES.
- Locate Daytime Running Lights (DRL) module under left side of instrument panel. Disconnect DRL module connector. If warning light turns off, go to next step. If warning light remains on, repair short to ground in Tan/White wire between DRL module and instrument cluster.
- Turn ignition off. Connect a test light between DRL module connector terminal "A" (Light Blue wire) and ground. See Fig 1. If test light does not illuminate, go to next step. If test light illuminates, repair short to ground in Light Blue wire between DRL module and park brake warning switch.
- Connect a test light between DRL module connector terminal "F" (Tan/White wire) and ground. See Fig 1. If test light illuminates, repair short to ground in Tan/White wire between DRL module and Diode 1, or Purple wire between Diode 1 and EBCM, or brake pressure warning switch. If test light does not illuminate, repair short to ground in Light Blue wire between ignition switch and DRL module. If Light Blue wire is okay, replace ignition switch.
Courtesy of GENERAL MOTORS CORP.