Rear air problem

[AUHUMMER]

OK, looking to the voice(s) of experience, and trial and error, again for help. Came out to the truck ('03 H2) this afternoon after a 5 minute stop and heard the rear air compressor running---checked it out a couple minutes but it never stopped. Drove on to work and it was still running after I turned off the ignition. Ran continuously for about 8-10 minutes while I crawled under and around looking for something wrong. I was headed into a meeting and knew it would run down battery so I pulled the VSES/ECAS fuse under the hood. Anyway, I searched the threads and, of course, found related threads. Until I can use the spray bottle test to look for leaks, IS IT OK TO JUST LEAVE THE VSES/ECAS FUSE OUT? Usually my repairs require multiple fixes---the original problem and then all the crap I tear up---so this may take a few days. If it is a bag, I'll have to order---no dealer within 100 miles. As always, thanks...

[MarineHawk]

Oh, I thought this thread was about flatulence.

[mdoyle]

It's likely a bag and they can be tricky, sometimes leaking badly and other times holding air for days. That threw me off when ours developed air suspension problems, I reasoned there was no way a leak in the bags could be intermittant- but that's exactly what it was.

Don't tear everything apart, just pull the bags and replace them. If it's an 03, there is a programming update you should inquire about for the air suspension.

While you're getting that update, tell them to also update everything else. Early 03's had an issue with the "auto volume" not sending a signal to the amp unless you cycle the button with the engine running.

[AUHUMMER]

Thanks, and as always I appreciate the help. Doesn't look like the bags are that big a deal to replace. I'll get this thing to the dealer eventually to check on those updates.

[IRA51]

anyone have a sorce for aftermarket replacement air bags ? the dealer is probably going to want big bucks . the sorce I get my Ford/Lincoln bags from will sell replacement bags for expiditions for $180.00 a pair landed,but he doesn't have a replacement bag for Hummers .

[AUHUMMER]

Anybody know if its OK to leave the VSES/ECAS fuse out( stop compressor running) until I can get this sorted out? Just trying to avoid compounding problems...

[working Hummer]

But the pump does not run when the truck is off. So what's the point of pulling out the fuse?:confused:

[HUMTECH]

If the compressor is running with the ignition off the most likely cause is the air suspension relay sticking. Seen many that would intermittantly stick on. Leave the fuse out till you get A new relay otherwise you will burn the compressor out if it runs continuously.

[AUHUMMER]

But the pump does not run when the truck is off. So what's the point of pulling out the fuse?:confused:
That's the point---it IS running with the ignition off.;) I was worried about running down the battery and possibly burning up that damned expensive compressor.

Thanks Humtech---I hate to ask this but where is the relay and how do I check or is it just easier to go ahead and replace it and see if that works? Where might I find on of those animals?

[HUMTECH]

On an 03 h2 it is located on the inside of the drivers side framerail right by the firewall. as of where to get one I only know of the dealer as its not just A standard relay. For the price I would just replace it, hard to test if its intermittant.

[AUHUMMER]

Thanks ---I'll start tomorrow. This makes sense---I was having a hard time blaming it on a busted bag when the compressor continued to run after shutdown. That part was buggin' me. I appreciate the advice. :D

[HUMMERcustoms.com/TAZ]

It will be Ok to pull fuse and run just to backup te advice given. If air is lost then You will be riding on the stops on rear of course with quite rough ride.

I have not looked at 03 but You chould have air holding tank on p;atform that pump is mounted on. They are plastic lines and possibly have a hole or tank could have a hole (not likely) unless exhaust got against it. Could be a bad connection on lines to pump.

If You are concerned about pulling fuse just in case something else may be controlled by it You can crawl under the back and look up to see air pump/tank unit and will see a plug running to it from a wiring harness. You can disconnect there and only issolate that setup of pump and tank. The unit is qute heavy but You can unbolt I think the forward bolts and lossen the back bolts so it will hang down and You could turn pump on and possble hear leak or feel it with hands.

I agree the relay would be the simplest to try first.

If I left something unclear do not hesitate to ask me to clarify.

TAZ

[AUHUMMER]

Found the relay. Its mounted on a bracket on the firewall about 4 inches below where the steering exits the firewall. I searched online and the forum but can't find a part number for the relay...anybody have that #?

I really HATE doing any electrical work on a car!!! Anything else is fair game but back in '74 I installed a CB radio in my first car, a 1974 Trans Am, and for 2 weeks after that, every time I stepped on the brakes all the interior lights would come on. But, if I can get the part, this shouldn't be a problem (famous last words). Thanks again for the help. And TAZ, thanks for the advice---I'm just really hoping its not a case of tracking and trial and error.

[MarineHawk]

... back in '74 I installed a CB radio in my first car, a 1974 Trans Am, and for 2 weeks after that, every time I stepped on the brakes all the interior lights would come on.

LOL.

[HUMTECH]

Don't have the part# but any GM dealer should be able to get you one. Ask for A ECAS relay(electronically controlled air suspension).

[AUHUMMER]

HUMTECH---you da man!! :dancingbanana: 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. :clapping: :clapping:

[timgco]

BY any chance do you have your air hose screwed on? THat causes issues also.

[AUHUMMER]

No, air hose is not screwed on. Guess it was just the relay.

[HUMTECH]

If you have any doors open including the liftgate the air suspension is disabled, maybe that was was your problem initially. glad it worked out for you.

[CBR_Raven]

I'm having a problem with my air suspension as well...

it's strange but my air suspension goes flat when i leave the truck parked for a while. i notice it more when i leave the truck parked overnight. however, if i push the button to raise the truck 2" in the rear before i turn the ignition off then it seems to be fine when i leave for days even. this makes me think that it can't be the airbags leaking but maybe something else going wrong. the truck has been parked for almost a week with the 2" ride height button activated and it stayed fully inflated. therefore it must not be the airbags. what could it be? pleas help :confused:

[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]

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]

:confused: 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. :confused:

[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]

HUMTECH---you da man!! :dancingbanana: 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. :clapping: :clapping:

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