D250 3/4 Ton Pickup 2WD V8-318 5.2L VIN R 4-bbl (1982)
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.
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.