THEORY OF OPERATION
ANTILOCK BRAKE SYSTEM (ABS)
The semitrailer brakes are equipped with a sensor to modulate ABS, axle by axle, using an Electronic
Control Unit (ECU) to prevent wheel lockup during braking on unstable surfaces. The ABS is automatic, applied
through the air brake system, and needs no operator assistance.
The M872A4 is equipped with two electrical systems, a 12-volt system and a 24-volt system. The systems
receive their power from the prime mover through the intervehicular cable assemblies. The intervehicular cable
assemblies are connected to the M872A4 main wiring harness that distributes the power. The 24-volt system
operates the blackout lights. The 12-volt system operates all non-blackout lights and the ABS system.
During normal operation (non-blackout), only the 12-volt power cable is required.
During blackout operation, both the 12-volt and 24-volt power cables are required.
END OF WORK PACKAGE