Ok, here's what I got. I had a tire that was almost flat so I got the air hose out and tried to use it, when I pushed the button in on the right rear compartment of the hummer nothing happened so I changed the tire when I got in to drive off the "SERVICE AIR SUPENSION" came on.
Sense then I have noticed that when I turn the key on the compressor will pump 3 or 4 time and then stop no big deal but the button on the dash and the one in the rear compartment for tires and what not have stopped working the Hummer seems to be lower than it should be and I don't here it adjusting like it use too it's not all the way down and the ride seems to OK. I haven't found any leaks in the bags or the air lines. Just another H2 mystery. Is there a relay that is controled by these 2 switches any wiring diagrams. Thanks Russ

 

Good luck finding a wiring relay. It may be that the switch is bad on the tire pump.location. If you have not used it before it could have a bad contact. I would try turning off and on a few times.

 

Don't know if your concerns are related. In order for the rear air pump to be used, the key has to be in the "on" position to power the air pump, thus sending power to the rear switch to operate the air pump. Can't remeber if it matters if the engine needs to be running, or if it's just a key "on" position. If the key is in the acc or off position, there won't be any power sent to the rear inflator switch.

The only air suspension switch on the dash, that i'm aware of from looking at mine, is the little switch above the center console that has an up and down lookin arrow next to a pic of the rear of the hummer. (hope i'm making sense here), which when pushed, will inflate the rear air bags and give xtra height to the rear of the H2. According to the owner's manual, this will only work under speeds of 10mph ( I think thats what it said), as it's speed dependent and meant for slow speed off road travel. If you exceed the speed of the operation, the air will be released to lower the rear-end of the H2 back to the auto-factory setting.

As far as the Air Suspension light or message being displayed, look to make sure that you didn't bump or damage the sensor or wiring located in the wheel well, on top of the frame by the rear wheels. Just by changing the tire with a spare, it shouldn't affect the auto air suspension, unless ofcourse you're putting a totally different size of spare on.

 

The engine does have to be running in order for the compressor to operate. Most of the relays are located in the engine compartment, driver side in a little box that you take the lid off to access.

If you find the compressor relay try swapping it out with another relay, just make sure the part #'s are the same.

 

Don't know if its related or not, but my Service Air Suspension message came on just recently. Took it to the Hummer dealer to diagnose, and they said my L.R. ride sensor connector was bad. $95 bucks for the sensor connector. Part came in and I just need to pick it up and replace it. Being a dealer tech for many years, (Ford) I always question a connector issue, so i'll be checking the wiring loom and sensor pins to see if maybe the connector was a shotgun guess, or needed replaced due to issues seen in the field.

 

Mine is a 03 when I raise the air bags, they will stay at the raised height until I lower it. The speed limit is only to raise it. example it will not raise if you are going over 20 mph I drive at speeds with it raised a lot of times.

 

It will deflate at 45mph back to normal.

 

Dam sorry everyone for not responding back to my problem. I replaced the connector per the dealer and it did not fix the problem. After I replaced the connector, and turned on the system (key-on), I thought it had been fixed until I was fiddling with the wire loom coming from the new connector. As I moved the wiring/connector, I could hear a "clicking" noise. I then lightly grabbed the leveling arm from the sensor and the clicking got even worse. Not enough to move the lever, but just enough wiggling to get the clicking noise to get even worse.

Ended up buying a level sensor and after the replacement I haven't had any issues.

 

I guess nobody read the manual... the Extended Ride Height button on the dash raises the rear body 2 inches above the stock ride height. WHEN THE TRUCK REACHES 40 MPH, not 10, not 20, but 40 MPH, the Extended Ride Height will disengage and the light will blink while letting the extra air out of the rear bags. Once the frame reaches the stock run height, the light will go out.

 

What I want to know is how to STOP the automatic EXTENDED HEIGHT aka airbag discharge when the truck reaches 40 mph. I want it to STAY UP at ALL SPEEDS.