For 1990-2009 cars

As the vehicle load increases, the vehicle body lowers enough so that the sensor arm rotates above the in-trim zone, the automatic level control sensor activates the internal timing circuit. If the vehicle maintains this condition for more than the minimum delay of 7-27 seconds, the automatic level control sensor completes a circuit to ground, which in turn completes the automatic level control relay circuit to ground. The automatic level control air compressor then supplies compressed air through the air dryer and air lines, to the air shocks.

Important: Do not overload the vehicle as automatic level control air compressor failure may result from excessive run time.

As the air shocks inflate, the vehicle body raises, causing the automatic level control sensor arm to rotate downward. Once the automatic level control sensor arm reaches the in-trim zone, the automatic level control sensor opens the automatic level control relay circuit, shutting off the automatic level control air compressor.