Abstract: A vehicle electrical system includes dual alternator/battery sets separately connected to separate non-critical electrical loads, and both connected through a diode circuit to a critical electrical load. A starter switch connects both batteries to the engine starter motor.

Abstract: An electronic control for a vehicle supplementary hydrostatic front wheel drive includes a rear sensor for providing a command signal representative of the speed of differential connected, engine-driven, main drive wheels. A front sensor provides a feedback signal representative of the speed of the hydrostatic drive motors. The command signal is modified to provide a modified command signal to be summed with the feedback signal to provide servo circuitry with a servo signal which is representative of the front wheels being driven 3% slower than the rear wheels. Electrically actuated, pressure responsive clutches allow the front wheels to overrun the hydrostatic drive motors until the slip at the rear wheels exceeds 3%, then the front wheels drive to supplement the main drive wheels.

Abstract: A motor grader is provided with an electrical control circuit for automatically effecting engagement, speed, and direction control of an auxiliary hydrostatic front wheel drive system to augment the primary engine-driven rear wheel drive system.