Circuit Operation

Power for the Rear Wheel Anti-Lock (RWAL) control module is supplied on circuit A20. This circuit is connected to the fuse block and protected by a 20 amp fuse located in cavity 14. Power for the fuse is supplied on circuit A22 from the ignition switch. This circuit is HOT in the START/RUN position only.

Power for the A22 circuit is supplied by circuit A2. This circuit originates at the Power Distribution Center (PDC) and is protected by a 40 amp fuse located in cavity 2.

Four fuses supply power for the Rear Wheel Anti-Lock (RWAL) Brake System. They are fuses 2, and 6 in the Power Distribution Center (PDC), and fuses 14 and 20 in the fuse block. Fuses 2 and 6 in the PDC, and fuse 20 in the fuse block are connected directly to battery voltage and are HOT all times. Fuse 14 in the fuse block is HOT when the ignition switch is the RUN Position.

In the RUN position, the ignition switch connects circuit A2 from a 40 amp fuse in cavity 2 of the PDC with circuit A22. Circuit A22 connects to a bus bar in the fuse block. The bus bar feeds circuit A20 through fuse 14. Fuse 14 is a 20 amp fuse.

On diesel engines circuit A20 is double crimped at cavity 3 of the RWAL control module and provides battery voltage to the vacuum switch.

Circuit F32 provides battery voltage to the RWAL module. Circuit F32 is HOT at all times. Fuse 20 in the fuse block protects circuit F32. Circuit A3 from the PDC feeds the fuse block bus bar that powers fuse 20 and circuit F32. Fuse 6 in the PDC protects circuit A3. Circuit Z3 provides ground for the RWAL control module.