GM Service Manual Online
For 1990-2009 cars only

Air Compressor

The air compressor is a positive displacement air pump, powered by a 12 volt DC permanent-magnet motor. The air compressor head contains intake and exhaust ports plus a solenoid-operated exhaust valve that releases air from the ALC system when energized. Air compressor intake air is drawn through an intake air hose and filter, mounted in the body rail. The air compressor is a serviceable part and is mounted on a bracket. The bracket is mounted to the rear suspension cradle.

Air Dryer

The air dryer is attached to the air compressor head assembly at the pressure outlet and provides a dual function:

    • It contains a moisture-absorbing chemical (desiccant) that absorbs moisture from the compressed air before it is delivered to the rear struts. Moisture is removed from the air dryer and returned to the atmosphere when air is exhausted out of the struts during lowering.
    • It contains valving that maintains a system pressure (residual pressure) of 48 to 97 kPa (7 to 14 psi). This system pressure is maintained for improved ride characteristics and improved air sleeve reliability.

Exhaust Solenoid

The exhaust solenoid is a non-serviceable part of the air compressor head and provides a dual function:

    • When energized, it exhausts air from the rear struts.
    • It acts as a relief valve to limit the maximum air pressure output of the compressor.