K 3500 Truck 4WD V8-454 7.4L (1994)
Brake Warning Indicator: Description and Operation
Brake Warning System
DESCRIPTION
Battery voltage is supplied to the BRAKE Indicator when the Ignition Switch is in RUN or START. When the ignition switch is turned to the BULB
TEST Position the Brake Warning Lamp lights.
Three Switches are connected to the BRAKE Indicator. When any one of these Switches closes, ground is provided and the Indicator lights. The
BRAKE Indicator is also connected to the Electronic Rear-Wheel and Four-Wheel Brake Control Modules.
PARK BRAKE WARNING SWITCH
The Park Brake Warning Switch provides a ground when the Park Brake is applied. The Park Brake Warning Indicator lights to alert the driver.
BRAKE PRESSURE WARNING SWITCH
The Brake Pressure Warning Switch closes to light the Brake Warning 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. This can only be accomplished after the faulty system has been repaired.
REAR-WHEEL BRAKE CONTROL MODULE
The Electronic Rear-Wheel Brake Control Module grounds the BRAKE Indicator when the Module senses a fault in the Antilock Brake System.
FOUR-WHEEL ANTILOCK BRAKE CONTROL MODULE
The Electronic Four-Wheel Antilock Brake Control Module grounds the brake warning indicator and the Antilock brake warning indicator lamps
when the module senses a fault in the Anti lock Brake System.
