S15/T15 Sonoma P/U 2WD L4-2.2L VIN 4 (1995)
Brake Warning Indicator: Initial Inspection and Diagnostic Overview
Circuit Operation
Battery voltage is supplied to the Brake Indicator through the Gauges Fuse and the PNK (39) wire when the Ignition Switch is in RUN or START.
Ground is provided through the TAN/WHT (33) wire by the Park Brake Warning Switch, Brake Pressure Warning Switch or the Electronic Brake
Control Module (EBCM).
The Park Brake Warning Switch closes when the Parking Brake is applied. The Brake Indicator lights to alert the driver.
The Brake Pressure Warning Switch closes to light the Brake Indicator when there is low brake fluid pressure in one of the two hydraulic brake systems.
This could be caused by a leak in one of the brake lines. Refer to Brakes and Traction Control for Switch reset procedure. This can only be
accomplished after the system has been repaired. See:
The Rear-Wheel Antilock Brake Module grounds the Brake Indicator when the Module senses a malfunction in the Antilock Brake System. The
Four-Wheel Antilock Brake Module grounds the Brake Indicator when the module senses certain malfunctions in the hydraulic portion of the system.
The Four-Wheel Antilock Brake Module grounds the Antilock Indicator when the module senses a malfunction in the electrical or electronic portion of
the system. Brake voltage input is supplied to both Modules through the Stoplamp Switch whenever the brakes are applied. For Rear-Wheel Antilock
Brake System And Four-Wheel Antilock Brake System Description and Diagnosis Refer to Brakes And Traction Control. See:
Troubleshooting Hints
1. Check the condition of the "BRAKE" warning lamp.
2. Check GAUGES fuse. If fuse is open, check for short to ground in PNK (39) wire between I/P Fuse Block and Instrument Cluster connector.
3. Check the grounds G102 and 0104 are clean and tight.
4. Check brake fluid level. If low, Refer to Brakes And Traction Control. See:
5. If brake fluid reservoir is empty or very low, and "BRAKE" warning lamp does not light, check Brake Pressure Warning Switch.
6. If equipped with Anti-lock Brakes and "BRAKE" warning lamp is lit, check for trouble codes. Refer to Brakes And Traction Control. See:
7. If equipped with VCM and "BRAKE" warning lamp is lit, check for trouble codes. Refer to Computers and Control Systems. See: Powertrain
Management/Computers and Control Systems
