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Discussion Starter #1
I've had a 2002 Envoy for about a year. When it's really cold sometimes (not always) the rear end will be really low in the morning. Usually it will pump right up and be fine for several days.

Then we noticed that on flat ground it would usually NOT pump up, but it we pulled it into the driveway which has a slight incline, it would trigger things to start working and get back to normal.

Today my wife called me and said it wasn't pumping up in a level parking lot. I told her to drive around and find an incline. She did and it blew right up.

I haven't tried to get under there and find leaks yet. I'm wondering if the "incline thing" means it could be one or both of the sensors.

Any idea how I could troubleshoot this some and figure out if it is the sensor(s)?

Looks like I can get Dorman sensors for $60 or $70 on Amazon.

Thanks in advance for advice!!!

Navyhoosier
 

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I'd put money on the sensors. You're gonna have to get out and under to figger it out.

I personally don't know this system, but as it's GM, it likely follows the same sensor/feedback to activate the air suspension in their older product line.

Leaks are important.... but fix the sensor(s) first. There has to be a dead-spot or a broken intermediate link on the sensor(s) ..... and the incline just shifts the weigh enough to get them to work.
 

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Discussion Starter #3
Looks like a sensor on each side.

From Amazon

  • Restores proper communication with Suspension Compressor
  • Failure sets off a warning light
  • Direct fit replacement
  • No special tools required
  • Original Equipment (OE) Number: 15070506, 25999461
No lights indicating failure, although the sensor could be working fine and however it gets "triggered" could be messed up.

Looks like about 60 bucks per sensor lifetime warranty.

Maybe I can try to jump or jiggle one side at a time and see if we can make it turn on that way.

Navyhoosier
 

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2006 gmc trailblazer_ls
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Having dealt with the crappy air suspension reliability issues on my 06 denali voy. Make your life easier and do the coil spring conversion. 100-200 and never need to worry about it again. It was by far one of the best mods besides my exhaust. I know alot of folks want to try and keep it and it gets very expensive over time. I had issues in winter it would deflate over night and take forever to fill back up. If worried about squatting towing just also install bag inside coil spring and inflate when your gonna tow.
 

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Discussion Starter #7
I'm interested in trying to keep the air system going, but I'm certainly not willing to spend big bucks at a shop to do it. I'm pretty handy and can probably sort things out with some online suggestions guiding me.

I would guess I've probably got two different issues going on (the more I think about it).

The random deflating is probably not related to only inflating on an incline.

You would think if it was a leak, it would be consistent (like cracked bags).

Any thoughts?

Navyhoosier
 

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2006 gmc trailblazer_ls
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Yeh if it was leaking i would think it would leak all time. Idk where your located but if im able to disconnect my rear sensors and nothing set warning off on my dash id send em to ya just pay shipping. I converted to rear coils and pulled compressor and lines. Left the sensors mounted on my frame and they still worked when i removed the bags
 

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Discussion Starter #10
anyone know where the deflate valve is? There has to be a method to let air out, perhaps that valve isn't doing it's thing.
 

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Also almost sounds like a compressor issues not a sensor. The sensors only control height. If sensor was bad then that side wouldnt work right not both sides. And i think its on the compressor itself should be able to let air out
 

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2002 gmc envoy_sle_xl
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If it turns out the rubber is broke on the linkage for the sensor I 3D print just the linkage and have them for sale on eBay. Been using a printed set for a year now no problem. It doesn't sound like that is the problem but figured I would let you know just in case.
 

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Wow! Totally feeling it here! You guys are stepping up and offering all sorts of help.

I've seen threads just linger, unanswered. This is very refreshing.

My first impression when I came to and saw this site was: "Why aren't these threads being answered, solved or closed?"
 

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2005 gmc envoy_slt
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Another vote for switching to coil springs. I did that many years ago and have been very happy. If you're interested in my used compressor let me know. Good luck
 

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Discussion Starter #15
Thanks for all the input. This morning it was parked on an incline and the back was "deflated". So I turned the key to on (without starting engine) and the compressor kicked on after just a few seconds. I'm going to get my wife to park it on level tonight, and hopefully it will be deflated in the morning.

Then, if it fails to "turn on" the compressor when on level, I guess I will try to jiggle both sides (one side at a time) and see if I can figure out what that part of the issue is.

I think the no pump up on level is likely different than whatever causes the deflate during the evening. (seems to be worse in the cold).

Thanks again.

NH
 

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2004 Trailblazer LS 4x4, 4.2L:, 2016 ATS-V, 2014 CTS-V Wagon, 2018 Audi A7
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While I don't have bags, I looked at an older Navigator with bags. They are notorious for going bad. I investigated and found that coils/shocks were the way to go. That's what I believe to be the best way to go in this situation as well.
 

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Discussion Starter #17
Most likely you are right. As long as things will eventually pump up, I'll probably try to troubleshoot this some and see if I can get it back. However, if I start having to spend more than the coils and shocks cost....I could see myself switching pretty quick. I really liked the auto-level feature and would hate to loose that.

NH
 

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Totally understood. At this point it's about how the dollars and cents work out.
 

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2004 gmc envoy_slt_xuv
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Totally understood. At this point it's about how the dollars and cents work out.
If you do not plan on doing any towing, replacing the airbag suspension is a good option. The "kits" to make the conversion are not that expensive and easy to install providing you have proper jacking/support tools. I mention "kits" as the stock dampers (aka shocks) need longer travel and the "kits" use progressive springs.
I tow and have rebuilt my air suspension.
Now for some details. The OEM compressor has a tendency for the check valve to fail. If not in the rust belt, the check valve assembly can be rebuilt. If in the rust belt area, replace the compressor with a Dorman (NOTE: If this is an XUV, stay OEM with the Arnot!! Experience).
The reason for staying with the air suspension for towing is the self leveling feature. Helps with the tail wag
 

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Discussion Starter #20
I do tow, yet I have better tow vehicles. Sometimes I use the Envoy on smaller trailers or put a platform out on the back.

Can you send me a link to information about rebuild.

I bought my Envoy not quite a year ago at an auction. 2002 model. I guess it had about 220k miles, super clean looking vehicle. I'm up to just over 230k right now.

So far not many problems. I bought it knowing the a/c was weird, but one $80 actuator and some time figuring things got that going. Changed all my fluids and cleaned up a bunch of leaks. Now trying to figure out which leaks I need to fix and which to just watch.

So...I'd love to try to keep it going.

Thanks

NH
 
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