I would suspect a leak in the rear air spring bags
check for leaks 1st and if pump running
Open hood and trunk.
Turn ignition off.
Place vehicle on flat surface.
Measure distance from ground to top of rear wheelwell opening.
This distance is unloaded height.
Turn ignition on, but do not start engine. Add 300 lbs. (136 kg) of weight to trunk. Allow at least 28 seconds for delay. Compressor starts
If compressor does not start and vehicle is within one inch (25.4 mm)
leak down issue and have to check electrical (let me know )
If compressor does not start and vehicle is not within one inch (25.4 mm) of unloaded height, perform HEIGHT SENSOR.
If compressor still does not operate after adjusting height sensor, check electrical system, fuses relays.
If compressor runs continuously, check for the following conditions.
If none of the following conditions exists, replace height sensor:
Stuck ELC relay.
Short to ground in Yellow wire between ELC relay and height sensor.
Short to voltage in Dark Green wire between ELC relay and compressor connector
Saturday, December 19th, 2009 AT 6:49 AM