Circuit Operation - Four Wheel Antilock (4WAL)

Battery voltage is supplied to the Brake Warning Indicator when the Ignition Switch is in RUN or START. Two Switches are connected to the Brake Warning Indicator. When either one of these Switches closes, ground is provided and the Brake Warning Indicator lights. The Brake Warning Indicator is also connected to the Electronic Four-Wheel Brake Control Module.

The Brake Pressure Warning Switch closes and provides a ground 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.

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 Four-Wheel Antilock Brake System. Module also grounds the Brake Warning Indicator for 3 seconds when the ignition is placed in RUN.