Brake Warning Indicator Always On
WARNING: This page is about a different car, the 2003 GMC Sonoma, 2003 GMC Jimmy, 2003 Chevrolet S10 Pickup, and 2003 Chevrolet Blazer. However, it is still accessible from the selected car via links, so may be relevant.
- Did you review the Brake Warning System description and operation and perform the necessary inspections? If so, go to the next step. If not, go to SYMPTOMS - HYDRAULIC BRAKES under TROUBLE SHOOTING.
- Turn ignition off for 5 seconds. Ensure the park brake is released. Turn ignition on while observing the brake warning indicator. Does the brake warning indicator illuminate for 3 seconds and then turn OFF? If so, See INTERMITTENTS under TROUBLE SHOOTING. If not, go to the next step.
- Install a scan tool. Select the INSTRUMENT PANEL CLUSTER SPECIAL FUNCTIONS menu on the scan tool. Command the BRAKE LAMP OFF. Does the brake warning indicator turn OFF? If so, go to the next step. If not, go to step 11.
- Select INPUT 1 from the BODY CONTROL MODULE DATA DISPLAY menu on the scan tool. Ensure the park brake is released. Observe the PARK BRAKE status on the scan tool. Does the scan tool display RELEASED? If so, go to the next step. If not, go to step 6.
- Disconnect the brake fluid level switch harness connector. Does the brake warning indicator turn OFF? If so, go to step 12. If not, go to step 8.
- Disconnect the park brake switch harness connector. Does the brake warning indicator turn OFF? If so, go to step 9. If not, go to the next step.
- Disconnect from the Electronic Brake Control Module (EBCM), the harness connector containing the park brake switch output circuit. Test the park brake switch output circuit for a short to ground. See appropriate wiring diagram under BRAKES in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Did you find and correct the condition? If so, go to step 14. If not, go to step 10.
- Disconnect from the EBCM, the harness connector containing the brake fluid level sensor signal circuit. Test the brake fluid level sensor signal circuit for a short to ground. See appropriate wiring diagram under BRAKES in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Did you find and correct the condition? If so, go to step 14. If not, go to step 13.
- Replace the park brake switch. See PARK BRAKE WARNING LAMP SWITCH under REMOVAL & INSTALLATION. After repairs are complete, go to step 14.
- Replace the EBCM. See REMOVAL & INSTALLATION in appropriate ANTI-LOCK article. After repairs are complete, go to step 14.
- Replace the instrument panel cluster. See appropriate INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. After repairs are complete, go to step 14.
- Replace the brake fluid level sensor. See MASTER CYLINDER FLUID LEVEL SENSOR under REMOVAL & INSTALLATION. After repairs are complete, go to step 14.
- Replace the EBCM. See REMOVAL & INSTALLATION in appropriate ANTI-LOCK article. Go to next step.
- Turn ignition off for 5 seconds. Ensure park brake is released. Turn ignition on while observing the brake warning indicator. Does the brake warning indicator illuminate for 3 seconds and then turn off? If so, the system is okay. If not, go to step 2.