Electrical Warning

The Four Wheel Antilock (4WAL) system is basically maintenance free. When working on this system, observe the following:
^ Before welding on the Vehicle with an electric welding,unit, turn the ignition switch OFF and disconnect the Electronic Brake Control Module (EBCM) connectors.
^ Do not use a fast charger for starting the engine.
^ Disconnect the negative battery cable when fast charging.
^ Never disconnect the battery from the vehicle electrical system with the engine running.
^ Make sure all wiring harness connectors are securely connected.
^ Always note the routing, position, mounting, and location of all components, wiring, connectors, clips, brackets, brake pipes, etc., when servicing the 4WAL system. Speed sensor wiring, routing, and retention is especially important to help prevent false signals due to electrical noise picked up by the wiring. Proper system operation can only be achieved if the system is restored to its original equipment condition.

The above mentioned items do not cover every possibility, but must be followed when working on 4WAL. When doing service work, become familiar with 4WAL and how it interrelates with other components on the vehicle.