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Discussion Starter #1
Hi, when i turn the ignition key I hear the air suspension compresor working But when I have my family in the back seat Tha car seats low How do I know what’s wrong? My car is a 1991 DeVille
 

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2003 Deville Base
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in most cases that will point to leaky shocks, leaky air lines, or mis adjusted sensor. It's not air suspension, it's level control. At key on, the compressor should come on for a few seconds and go off. If it comes on while you're driving, with no one in the back, then start looking for leaks. A squirt bottle of soap suds will help. Not sure if OBD1 monitored the compressor
 

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Discussion Starter #3 (Edited by Moderator)
in most cases that will point to leaky shocks, leaky air lines, or mis adjusted sensor. It's not air suspension, it's level control. At key on, the compressor should come on for a few seconds and go off. If it comes on while you're driving, with no one in the back, then start looking for leaks. A squirt bottle of soap suds will help. Not sure if OBD1 monitored the compressor
It comes on for a few seconds and then stops like you say but when someone after gets in the back seat the car gets low

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start the car. open the trunk. get two or three people to sit on the back. see if you hear the compressor run. If it runs but doesn't level the car, then you're looking for a leak in the lines or possibly bad shocks. Beyond that we need Bass, Sub or one of the other experts to chime in, since I am not absolutely sure your 1991 has the same set up as my 2003
 

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Discussion Starter #7
start the car. open the trunk. get two or three people to sit on the back. see if you hear the compressor run. If it runs but doesn't level the car, then you're looking for a leak in the lines or possibly bad shocks. Beyond that we need Bass, Sub or one of the other experts to chime in, since I am not absolutely sure your 1991 has the same set up as my 2003
Ok i try that but I have my compressor in the engine compartment I think
 

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Now I have tried the compressor runs a couple of seconds after I start the engine and after that it stops. I also put people in the back and the compressor doesn’t start
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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The system does a 2 or 3 second proveout - preload about 6 seconds after Key: ON. It should then stay off unless weight in the trunk or rear seat changes. If you load more people and the system doesn't compensate quickly you have height sensor or electrical problems.

Trouble codes?? Subscribe to the correct year/model of GM/Cadillac service manuals at www.alldatadiy.com.
 

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The system does a 2 or 3 second proveout - preload about 6 seconds after Key: ON. It should then stay off unless weight in the trunk or rear seat changes. If you load more people and the system doesn't compensate quickly you have height sensor or electrical problems.

Trouble codes?? Subscribe to the correct year/model of GM/Cadillac service manuals at www.alldatadiy.com.
No I don’t get any trouble codes strange.

What kind of site is that is it better than buying Hayes?
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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Use the Haynes for mopping up oil spills. FAR too generic to be of use.

Alldata is the online site for the original "factory service manuals".

You could also look for the original Cadillac/Helm paper manuals on eBay. They're out of print at www.helminc.com - the original publisher for many "factory service manuals".
 

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how did you check for trouble codes? Also, if you mean Haynes manual then yes alldatadiy.com is way better. Haynes and Chilton are far too general.
 

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how did you check for trouble codes? Also, if you mean Haynes manual then yes alldatadiy.com is way better. Haynes and Chilton are far too general.
I push warm and off

how did you check for trouble codes? Also, if you mean Haynes manual then yes alldatadiy.com is way better. Haynes and Chilton are far too general.
I push warm and off
 

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How do I check if the sensors bad and how do I fix them? Is there a Quik fix?
we'll need someone with a '91 to chime in. If it's like later models the "sensor" is mechanical. Sorry, but I am not that familiar with your year model.
 
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