Rear air problem

[mdoyle]

I think it's still the bags, my 03 did the same thing; it would lose air overnight but if I raised the rear it would stay up for days.

The bags develop cracks right where they flex similar to those rubber coin purses- they open when you bend them, so if you raise the rear the cracked area of the bag stays flat and doesn't leak.

After driving myself crazy looking at everything else in the system, I finally had the bags replaced and months later, they are still fine.

[CBR_Raven]

Originally Posted by mdoyle

I think it's still the bags, my 03 did the same thing; it would lose air overnight but if I raised the rear it would stay up for days.

The bags develop cracks right where they flex similar to those rubber coin purses- they open when you bend them, so if you raise the rear the cracked area of the bag stays flat and doesn't leak.

After driving myself crazy looking at everything else in the system, I finally had the bags replaced and months later, they are still fine.

yeah, i guess that makes sense. i'll replace the bags and see what happens. i guess it would be about time for the bags to be replaced on an '03 anyway.

[CBR_Raven]

ok this is weird...something told me to just disconnect the battery for a while and see what happens before i go spending money to replace anything. well, i did just that and now the truck seems to be fine after i let it sit overnight.

[HUMTECH]

If you still have the original single stage compressor that the 03's came with I believe there is A calibration update for excessive cycling which will cycle on the exhaust valve and over time deflate the bags even with the key off. If you have the dual stage compressor they are not programmable and you have to have it diagnosed, likley the assembly would need to be swapped out as parts are not available

[CBR_Raven]

Originally Posted by AUHUMMER

HUMTECH---you da man!! Got the relay from the GMC dealer 25 miles away--local didn't have it. Got home and it wouldn't fit. I had asked for a ECAS relay for '03 Hummer H2. This time I followed my own long standing rule---take the part with you-- and they swapped it out. He looked it up again, and showed me where his data base had it wrong. Anyway, the correct part # is 15319851. I installed relay, put the fuse back in and ...bingo...we have air. I think it had to readjust itself or something because initially the compressor did not turn on. It didn't air up to normal ride height until I drove to work. Everything appears to be back to normal. Thanks again for the advice from all you guys---I was really dreading troubleshooting all that plumbing.

thanks for the part #...i changed the relay out on mine as well. it was only a 10 minute job