[TopherS]

Our Rendezvous doesn't have many options, but perhaps that yours is a CXL, you have a lot of options we don't.

Do you know if you have automatic rear leveling system (keeps the car level, regardless of how it's loaded)? Our Park Avenue has that system and you can hear the compressor pumping up the rear shocks after you get in and start the car. It will also activate if the car is turned to on, but not started. Sometimes, the air-shocks will need a little air as you are driving and so you might hear the compressor working occasionally while driving (the computer is supposed to continually monitor the level as you drive and make adjustments if deemed necessary).

If you have that system, you can verify that it is the compressor by loading the back with weight (service manuals usually say 300lbs, but just have a person sit in the back). Close all the doors, then turn the car to on, but don't start it. There should be a few seconds before the compressor will kick in. If you hear it pumping up the rear and that's the sound you're concerned with...then you will know it is only that system.

If it is just that system and you only hear the noise after starting the car and on occassion while driving, then you shouldn't be too concerned. If your compressor activates a lot, it is an indication that you have a leak in the system somewhere (usually in the air-shocks or the air-line connections).

Hope this helps.