System Operation

When ride height decreases due to weight being added to vehicle, height sensor arm assembly rotates upward in relation to height sensor. See Figure . This activates a timing circuit in height sensor. After a delay of 17-27 seconds, height sensor grounds compressor relay, turning on compressor. Air is then pumped into the shock absorbers, raising vehicle. Delay prevents system from operating during normal changes in ride height that occur during driving. As vehicle rises, height sensor rotates downward. When vehicle rises to within one inch (25.4 mm) of curb height, height sensor opens ground circuit to compressor relay, turning compressor off.

When ride height increases due to weight being removed from vehicle, height sensor arm assembly rotates downward. This activates the timing circuit in height sensor. After a delay of 17-27 seconds, height sensor grounds exhaust solenoid valve circuit, causing air to be vented from shock absorbers, lowering vehicle. When vehicle lowers to within 1" (25.4 mm) of curb height, height sensor opens exhaust solenoid valve circuit, causing exhaust solenoid valve to close.

To ensure system is operating with at least minimum air pressure, height sensor commands an air replenishment cycle each time ignition is turned on. An internal timer circuit is activated when ignition is turned on. After a delay of about 35-45 seconds, compressor turns on for 3-5 seconds to ensure residual system pressure exists. If weight is added to or removed from vehicle during 35-45 second delay, air replenishment cycle will be overridden and vehicle will rise or lower after normal time delay.

Voltage is applied to compressor, compressor relay, inflator timer and height sensor at all times. This allows system to vent if load is removed with ignition off. Height sensor limits compressor operation or exhaust solenoid energized time to about 4 1/2 and 7 1/2 minutes. Time limit is necessary to prevent continuous compressor operation in case of air leak or continuous exhaust solenoid operation. Turning ignition switch from OFF to ON position resets compressor operation or exhaust solenoid valve energized time.