Where can I find a manual or tech drawing of the.

He air suspension system includes the following major units:

An Electronically Variable Orifice (EVO) control module, located to the right of the glove compartment, controls both the suspension system and the power steering boost.
Height sensors, located parallel to LH and RH front wheels and LH rear wheel, send a continuous voltage signal to the control module relative to the positions of the wheels and body.
A speed sensor, located on the transmission housing at the forward end of the extension housing, sends a signal to the control module to lower the vehicle at 65 mph and to determine the amount of power steering boost commanded by the control module.
Air spring solenoids are located on the air springs at each wheel. The control module opens these solenoids to let air into or out of the air springs.
A vent solenoid, located on the rear of the compressor assembly, opens on command from the control module to remove air from the air springs.
The ignition switch. The signal sent to the control module when the switch is in RUN position commands the module to control both steering boost and the suspension system.

NOTE : The air suspension system remains active for one hour after ignition switch is turned OFF. This allows for trim correction after passengers and cargo have been removed.
This system is a microprocessor controlled active air suspension system. The microprocessor constantly determines the height position of the vehicle body relative to the wheels. System operation is maintained by the addition or removal of air to or from the air springs, resulting in a predetermined front and rear suspension height. This predetermined height is known as the vehicle trim height. The system maintains a predetermined trim height regardless of road conditions or vehicle passenger load.

The microprocessor also uses vehicle speed to determine the proper trim height of the vehicle. At 65 mph, the suspension system lowers the vehicle trim for a more stable high speed profile.