3500 HD Models

CLEARING ABS DIAGNOSTIC TROUBLE CODES (RWAL)

Data Link Connector:

ZPRWAL SYSTEM
Zero Pressure Rear Wheel Antilock (ZPRWAL) is used on the 3500 HD model. The ZPRWAL system is used on rear disc brake systems because of the large volume of fluid the disc brake calipers need. The accumulator for this system is much larger than the Rear Wheel Antilock (RWAL) system. The Electric Brake Control Modules (EBCM) are identical in size and mounting configuration. The only noticeable difference is the color of the electrical connector. The RWAL EBCM has a black electrical connector and the ZPRWAL EBCM has a gray electrical connector. RWAL is used on all models with rear drum brakes except for Four Wheel Antilock (4WAL) applications.

1. Turn ignition switch to Off position, then pull Stop/Hazard fuse.
2. Turn ignition switch to On position, then proceed as follows:
a. Ground terminal "A" to terminal "H", for one second.
b. Remove ground for one second.
c. Ground terminal "A" to terminal "H" for one second.
d. Remove ground.
3. Brake lamp should turn off.
4. Turn ignition switch off, then replace Stop/Hazard fuse.