Brake Fluid Pressure Sensor/Switch: Testing and Inspection

Brake Warning Switch Testing
1. Raise the car on a hoist and open a wheel cylinder bleeder while a helper depresses the brake pedal and observes the warning light.
2. If the light fails to light, inspect for a burned out bulb, disconnected socket, or a broken or disconnected wire at the switch.
3. If the bulb is not burned out and the wire continuity is uninterrupted, check the service brake warning switch operation with a test lamp between the switch terminal and a voltage source.
4. If light still fails to light, disconnect the brake tubes from the valve assembly and install a new valve assembly.
5. If a new valve is installed, bleed the system.

CAUTIONS:
- Do not disassemble valve to reset the piston.
- The warning switch is not serviced separately. Do not remove the switch or attempt to repair.

NOTE: After repairing and bleeding the brake system, applying the brakes with moderate force will hydraulically recenter the piston and automatically turn off the warning light.