My 2005 DTS is sagging pretty low in the rear. No shop manual. Looked through a few forums here, found a bit of good info, but am in need of more.

Compressor does not appear to run (can't hear anything) when I turn the car on. Checked the fuse - it's OK.

1 - Where do I find and how do I test the load / levelling sensor(s)?

2 - Where do I find and how do I test the compressor?

3 - Can I just swap the relay with a similar one in the fuse block (to test the realy operation)?

4 - Is there anything common, other than the fuse/sensor/relay/compressor that could be at fault?

Thanks!

Dan

 

If fuses check out to be good and still no signs of the compressor turning on im going have to say that the compressor is probably shot. this is common and usually requires replacement. which new is extremely expensive. or you can save money and risk buying a used one that may not last long. Also check the rear struts to see if the rubber bladders are in good shape (cracks holes etc). I had this issue on my seville and replaced the rear struts and still had issues and it was due to the compressor. so heres what i did. i cut the compressor air lines and put in a "T" valve in place and aired it up manually. Its worked great, no there isnt auto leveling but i put in about 50psi and with 2 people in the back it rode fine and didnt sagg like it use to. Heres my write up on how i did my setup. this was about $15 bucks and 30-45 minute job.

https://www.cadillacforum.com/forum/...project-11893/

 

OK, my rear shocks were pretty much shot. Replaced them with Arnott AS-2121. Also replaced the damaged air lines with a good salvage yard set, out of a 2001 Deville. I took the compressor, too, not being certain that mine was dead, and swapped it, as well.

I pumped up the shocks and they (and the lines) hold air and ride well. I hot-wired the compressor (temporarily) and it operates properly. Incidentally, the original compressor does, too, so I'm keeping it as a spare.

After replacing and testing the components, I loaded the trunk with about 350 pounds of stuff (including me sitting on the edge) and, with the key on in the 'run' position, I got no response from the load-leveling system. It's possible, I guess, that the car did not go down far enough to trigger it.

Is there a minimum amount of drop to trigger it?

Can I reset the system to see its current level/attitude as its "normal" state, by disconnecting the battery (or some other method)?

Any and all feedback and suggestions are welcome. Thanks!

 

it should level it out automatically. but in your case you might have a code set and it may have just need cleared. otherwise the sensors may be bad which are located by the struts towards the bottom of them. they have an actuator arm looking thing and they also can be adjusted to set the right height if they get out of spec. otherwise it sounds like your on the right track.

 

I'm having the same problem with my '89 Deville and have pretty much boiled it down to the height sensor at the rear wheel suspension.

When you ground the test lead at the compressor and it pumps up OK that pretty much shows that everything is working in the system except that there is no signal from the height sensor.

That test lead at the pump bypasses the height sensor but doesn't bypass anything else in the system. When the test lead is grounded the pump won't work unless all the fuses and the relay (except the air exhaust relay) are good.

It could be a bad ground at the sensor or a poor connection, that will be my next check.

 

Well, sure it does have an actuator arm factor and they also can be modified to set the right size if they get out of specifications. otherwise it appears to be like yours.