Automatic Level Control

The Automatic Level Control (ALC) keeps the rear of the vehicle at a constant height. If weight is added to the vehicle, the Auto Level Control Sensor turns on the Auto Level Control Compressor. Air is pumped into the shock absorbers until the vehicle is level.

An Actuator Arm is connected between the rear axle tie rod and the Auto Level Control Sensor which is mounted to the rear crossmember. it turns as the vehicle height changes. A solid state unit detects this motion and operates switches to control the air flow into and out of the shock absorbers.

Voltage is applied at all times to the Auto Level Control Sensor, Auto Level Control Relay, Auto Level Control Compressor Vent Solenoid and Auto Level Control Inflation Timer Relay. This allows the Auto Level Control system to lower or raise the vehicle height even with the Ignition Switch in "OFF." Voltage is applied to the Auto Level Control Sensor with the Ignition Switch in "RUN," "BULB TEST" or "START." The Compressor, after an initial delay of approximately 40 seconds, will run for a few seconds to charge the system when the Ignition Switch is turn to "RUN."

The Auto Level Control Sensor delays 8-15 seconds after a change in vehicle height before closing switch C in the Auto Level Control Sensor. This prevents system operation during normal ride motions. in addition, the Auto Level Control Sensor limits Compressor run time or Vent Solenoid energized time to a maximum of 5 1/2 minutes.

This time limit is necessary to prevent continuous compressor operation in case of a severe system leak or continuous vent. Turning the ignition Switch to "OFF" and back to "RUN" resets the 5 1/2 minute maximum run time.