2002 Pontiac Aztek Owner's Manual - Page 277

Electronic Level Control (Option) On vehicles equipped with the optional electronic level control, the rear of the vehicle is automatically kept level as you load or unload your vehicle. However, you should still not exceed the GVWR or the GAWR. See "Loading Your Vehicle" in the Index. If the ignition key is in ACCESSORY, ON or when RAP is active, you may hear the compressor operating when you load your vehicle or shortly after you start your vehicle, and periodically as the system self-adjusts. This is normal. See "Retained Accessory Power" in the Index. The compressor should operate for brief periods of time. If the sound continues for an extended period of time (longer than one minute) or occurs many times within one trip, your vehicle needs service. Using heavier suspension components to get added durability might not change your weight ratings. Ask your dealer to help you load your vehicle the right way. Towing a Trailer CAUTION: If you don't use the correct equipment and drive properly, you can lose control when you pull a trailer. For example, if the trailer is too heavy, the brakes may not work well -- or even at all. You and your passengers could be seriously injured. Pull a trailer only if you have followed all the steps in this section. Ask your dealer for advice and information about towing a trailer with your vehicle. 4-36