Compressor Assembly, Air Suspension: Operation
All pressurized air suspension components contain high pressure air (up to 220 psig). Use extreme caution when inspecting for leaks. Wear safety goggles and adequate protective clothing when inspecting or servicing the air suspension system. A sudden release of air under this amount of pressure can cause possible serious or fatal injury.
Before performing any service on the air suspension system, the system must be disabled to prevent the system from changing ride height. Before any given component is to be serviced it must be deflated. Servicing the air suspension system without the system disabled, or with pressure in any specific component, can cause possible serious or fatal injury.
The Air Supply Unit (ASU) is made up of two primary components, the compressor and the valve block. There is a single pressurized air line between the compressor and the valve block to maintain system pressure. Control of the air compressor and valve block is from the Air Suspension Control Module (ASCM). Diagnose the air suspension system using a scan tool.
Air Compressor The compressor is used to add compressed air to the rear air-springs to raise the rear of the vehicle as well as to refill the reservoir. There is a desiccant located inside the compressor for moisture protection, and an air suspension hose assembly attached to the air compressor (including a filter) which are not pressurized, and can be replaced as an assembly. If water is visible in the filter, the air suspension hose assembly and the ASU must be replaced . An air suspension temperature sensor is attached to the air compressor bracket to monitor ambient air temperature for protection of the compressor.
Positive voltage is from a 40-amp fuse located in the PDC, and a normally open compressor relay (ASCM controlled) located in engine compartment area. The ground for the compressor relay is controlled by the ASCM.
Valve Block The valve block controls the flow of air in the system and to maintain the pressure in the in each air spring which allows the system to move each corner of the vehicle up or down as necessary. Valves and solenoids in the valve body increase or release pressure to air lines that connect to each pressurized component. The ASCM determines pressure from an internal pressure sensor in the valve body. The air lines connected to the valve block are labeled for identification only. The air lines are serviced as an assembly only.