Automatic Level Control (Alc)

The Automotive Control keeps the rear of the vehicle at a constant height. If weight is added to the vehicle the Automatic Level Control (ALC) Sensor turns on the ALC Air Compressor. Air pumped into the shock absorbers until the ALC Sensor senses that the vehicle is level. An Actuator Arm is linked between the upper RH Control Arm and the Sensor, which is mounted to the rear crossmember of the frame. It turns as the vehicle height changes. The Sensor detects this motion and operates switches to control the air flow into and out of the shock absorbers.

Voltage is applied. at all time the Compressor by Underhood Electrical Centre Fuse #1 and to the Sensor by I/P Fuse block Fuse #27. This allows the ALC System to vent after a load is removed. Voltage is also applied to the Sensor by I/P Fuse block Fuse #12, with the ignition Switch in "RUN," "BULB TEST" or "START."

To ensure that the shock absorbers are filled with adequate residual pressure, the Compressor Motor will run for 3 to 5 seconds, approximately 35 to 50 seconds after the Ignition Switch is turned to "RUN."

The Sensor must detect a "Car-Low" or "Car-High" state for 7-14 seconds before activating the intake or exhaust outputs. This prevents system operation during normal ride motions. In addition, the Sensor limits Compressor Motor run time or Exhaust Solenoid energized time to a maximum of 4.5 to 7 minutes.

This time limit is necessary to prevent continuous Compressor Motor operation in case of a severe system leak or continuous vent. Cycling the Ignition Switch to "OFF" and back to "RUN" resets the 4.5 to 7 minute maximum run timer.