ABS Circuit Description

WARNING LAMP OPERATION
The Zero Pressure Rear Wheel Anti Lock (ZPRWAL) system uses the existing BRAKE warning lamp in the instrument panel to indicate system operation and malfunctions. The BRAKE lamp is also used to show a hydraulic system pressure differential condition and parking brake operation.

NORMAL OPERATION
A bulb check occurs each time the ignition switch is turned "ON." The BRAKE lamp should light, remain on for about two seconds, then turn off. When system malfunctions occur, the BRAKE lamp will turn on and stay on until the malfunction is corrected. To determine the specific cause of a malfunction, refer to Functional Test. Testing and Inspection / Procedures / Functional Test.

The BRAKE lamp will also light when the parking brake is applied or the combination valve switch is activated. Do not confuse these functions with an ZPRWAL system malfunction.