Rear Electronic Leveling System
 

The other day I walked out to my car to notice the rear end was jacked up higher than normal. I researched the topic on here and feel like it is the height sensor, but I wanted to get some additional insight prior to spending the nearly $200 bucks on this part from gmpartsdirect.

Here was my troubleshooting:

1. Relieved the pressure in the rear shocks by disconnecting the air line on the driver side rear wheel. The car lowered.
2. Placed the airline back on.
3. Turned the car on.
4. Compressor continued to run until I pulled the relay (or shut the car off). I let the compressor run for over 60 seconds when it usually runs for 5-10 seconds.
5. I depressurized the air again.
6. Started the car and pulled the relay again when I was "comfortable" with the height.

I am currently running in this fashion.

This sounds like the height sensor since the compressor continues to run. Is there anything else I might be missing? Is there another "test" to see if it is the height sensor?

If it is the height sensor, where exactly is it located and what is the difficulty in replacing?

Thanks for the assistance.

the height sensor should be hooked to one of the control arms in the back. the relay could be bad, do you hear it clicking? the rear integration module controls the compressor, it gets a signal from the level sensor and the trunk switch< that could be left on or wire shorted as well

i would try unplugging the level switch and see if it stops, if so its likely something with that.
https://www.gmforum.com/attachment.p...ine=1398969090

Thanks for the responses jwfirebird.

As for the relay is there a way to check if it is bad? I assumed that the compressor did not run when it was unplugged and did when plugged in that the relay was working. Could it be bad and still run the compressor?

The wiring diagram will help and I will investigate next week (I am on vacation til late next week) .

I did play with the rear switch and it seems to be working. When the compressor was inflating the shocks I would depress the button and it would shut off the compressor. Then within about 3 seconds it would automatical, y turn back on. I did this a few times with the same result.

I will report back what I find out later next week.

What JW is saying, is the relay could be stuck in the closed position.....try swapping with another relay in the fuse block.....if it still continues to rise without stopping, then pull it......

Could be a bad integration module, grounded circuit #321, or a bad level sender....a scan tool would be needed to read level data in the rear integration module....

About all you can do, is disconnect C2 at the rear integration module.....if the pump continues to run, then you have a short to ground in circuit #321....if it shuts off, then it's the module or the level sender....with relay removed, back probe C1/B6 for ground, C1/A6 for 5 volts......now back probe C2/A9 read voltage at the car's normal level.....disconnect the level sensor arm....move the arm down ....read voltage....move the arm up...read voltage.....the voltage should change from the normal level(I'm guessing 2.5 volts), and go high and then low when you move the arm to the two extreme ends.....If that signal voltage does change like this, could be the integration module...

Thanks, Tech II. I will dig into this when I get back from vacation and report back.

Cheers.

In the future if you keep having the problem, and you replace the struts, you could convert to gas ones, or get a kit that will let you inflate/deflate them manually, I don't have a link to how to do so, but I am sure Justin will stop back by with the link to when he did his.
Of course this is not a fix, just a work around if you do not want to convert to gas struts.

well its up to you if you want to fix it but when my 98 started leaking from the rubber parts of the strut, it took out the compressor and that was a couple hundred for a used or rebuilt compressor and 150 for new struts. one of the guys who used to be one here alot suggested the ak29 which is just air lines that have a tire valve on it. after putting new stock type struts and this kit on it you almost never(like once a year) have to put any air in it. 10 bucks is alot better than a few hundred