The compressor is computer controlled and it's more likely a sensor fault. Before you start replacing costly parts check wiring and compressor relay
Air Suspension Height Sensor
Rear height sensor is located on scissor bracket between spare tire and right rear shock absorber. Try turning system off leaving a while then turning back on. See if this corrects fault?
Air Suspension Switch
Air suspension switch is located on left side of luggage compartment, in jack storage area.
NOTE:Electronic suspension system may also be referred to as the Load Levelling Control system, Dynamic Suspension system or Automatic Ride Control (ARC) system.
Rear air adjusted suspension is air-operated and computer-controlled. Air suspension system utilizes air adjustable shock absorbers to provide variable vehicle ride height depending on load and driving conditions. Shock absorbers also incorporate computer controlled two-stage (firm and soft), damping capability. Smooth ride is provided for normal driving conditions. If conditions require additional shock absorber damping, air suspension control module adjusts each shock absorber separately in response to load, road and driving condition inputs received from height sensor, Vehicle Speed Sensor (VSS), Throttle Position Sensor (TPS) and 2 steering sensors. On 4WD applications, transfer case inputs are also utilized.
Air suspension system is operational with ignition switch in RUN position, and has limited operation for 40 minutes after ignition is turned off. The air suspension switch, located in left rear corner of vehicle, must be turned off when vehicle is being hoisted, towed or jump-started.
A CHECK AIR SUSPENSION warning light is located in message center, to right of instrument cluster. Warning light stays on when air suspension is turned off or a system malfunction is detected.
Air required for leveling vehicle is distributed from air compressor to rear fill solenoids through nylon air lines. Air system can be pneumatically separated from side to side by control module activation of rear gate solenoid. This separation provides vehicle stability during roll conditions.
For safety during loading and unloading, vehicle height is memorized and maintained when any door is opened. Vehicle will return to commanded height when doors are closed or vehicle speed exceeds 10 MPH.
AIR COMPRESSOR ASSEMBLY
The air compressor assembly consists of an air compressor and vent solenoid. Neither is serviceable. The air compressor assembly is mounted above spare tire in the rear of the vehicle. The air compressor is powered through a relay, which is controlled by air suspension control module.
Pressurized air from the compressor passes through a drier containing a drying agent. Moisture is removed from the drier when vented air passes out of system during vent operation. Drier may be replaced separately.
AIR COMPRESSOR RELAY
Air compressor relay is mounted in relay module located next to battery junction box. Relay, controlled by air suspension control module, provides high current flow required to operate air compressor motor.
Sunday, November 30th, 2008 AT 5:51 AM