Unloading the Vehicle

As a load is removed from the vehicle. the vehicle body raises, causing the height sensor arm to rotate downward, If the body raises enough such that the sensor arm rotates below the in-trim zone, the height sensor closes switch A and activates the internal timing circuit. If the vehicle maintains this condition for more than the minimum delay of 7 to 14 seconds, the height sensor closes switch C, completing the exhaust solenoid circuit to ground. With the exhaust solenoid energized, compressed air exhausts from the shocks, through the airlines, air dryer exhaust solenoid, and air filter, and the vehicle body begins

As the vehicle body lowers, the height sensor arm begins to rotate upward. If enough load remains in the vehicle, the height sensor arm may reach the in-trim zone, causing the height sensor to open switch A, opening the exhaust solenoid circuit. This de-energizes the exhaust solenoid and prevents further air from escaping the system. If very little or no load remains in the vehicle, the height sensor arm may not reach the in-trim zone. In this case, the height sensor opens switch C (de-energizing the exhaust solenoid) after the electronic timer expires, approximately 5 1/2 minutes. This timer prevents continuous energizing of the exhaust solenoid, and is reset by turning the ignition switch to OFF or RUN, or whenever the sensor arm remains above the in-trim zone for 7 to 14 seconds or more.

In case of a system leak, a similar timer prevents continuous operation of the compressor by opening switch C after 5 1/2 minutes. This timer is reset by turning the ignition switch to OFF or RUN, or whenever the ignition switch is in the RUN position and the sensor arm remains below the in-trim zone for 7 to 14 seconds or more.