Hello all, the other day when I went to leave the rear of my navigator was all the way down. This is comon when its parked but as soon as you put it into gear the pump kicks on and it raises up...but the pump never turned on so it is stuck down. I checked all of the fuses that had to do with the air suspension including the high voltage ones under the hood. Do you think it is the compressor, or a relay or something...has anyone else had this problem?

 

your compressor is more likely bad but id go have it tested

 

This line says it all. "This is comon when its parked but as soon as you put it into gear the pump kicks on and it raises up..."
It sounds like you have had a leak for some time. It not only leaked when you were parked, it leaked continuosly while you were driving causing the pump to constantly run to keep up with the leak. The compressor was not designed to do this and is now worn out. If leaks (overnight sagging) are fixed promptly, the compressor will last the life of the truck.
At this point you will need a compressor and probably both rear air springs.

The air springs have a finite life span, usually 8-10 years, sometimes less depending on conditions. They usually leak where the bottom of the bladder folds in on itself. Any cracking at the fold indicates a spring that is either leaking, or very soon will be.

 

Thank you so much for your input. The compressor did always kick on everytime you put it into gear from being parked and sometimes when the road was uneven. When is it normal for the compressor to kick on and off? I am going to the dealer tomorrow.

 

Ideally, the compressor will only run after a load (people, cargo) is added to the truck to bring it up to trim height. When the load is removed, the system should vent down to trim height. There will normally be a SMALL amount of leakage overnight and the compressor may run for about 5-10 seconds or so after startup to adjust the suspension. (This actually "shouldn't" happen, but the system is never 100% airtight).
The compressor shouldn't really run at all while driving, maybe 10 seconds per hour. I'm sure there is a spec somewhere, but I've never seen it. If yours was running when driving on uneven roads, this indicates leaks in the springs. They usually crack where the bladders fold under on themselves. The suspension travel flexes the cracks and lets air escape, causing the compressor to "keep up" with the leak.
If you are at all mechanically inclined, replacing the springs and compressor is very simple. It's nothing at all like coil springs. Check here for parts: http://tinyurl.com/34859x
At the dealer, I would estimate the price for the parts alone to be about $250ea for the springs and $400 for the compressor. Add diag and labor and the repair can get really pricy.

You didn't specify the year or if the truck is 2x4 or 4x4. The 4x4 will have air springs or shocks in the front also. If they don't seem to be leaking, they may be ok for a while. Just keep in mind that they will be the next to go.
Good Luck

 

Thank you lsrx101. It is a 4x4 so it's good to know about the front shocks. I took it to the dealer today and the mechanic found the B1566 code (Door Ajar Circuit Short To Ground). He lubed all of the switches and now it is working fine. I asked him why the door ajar light in the dash board wasn't on and he told me that it doesn't always come on when it sends the message to the computer. I also asked him about the bladders and he said they seemed ok but to keep an eye on them in the future due to the mileage. They only charged me with the Diagnostic fee ($95), it appears that I got lucky on this one! Unrelated to mechanics, I do have an expertise in the print media/web design field if you every have any questions or needs that I could return a favor to you feel free to contact me through my website stronggraphics.us Thanks again. Happy holidays & new year. -Phil