2001 Denali Autoride Problems

jeff5295 · June 5, 2011

I did a lot of seraching on this site and still haven't found a solution, hoping someone can help. I found a link to a long post on an Escalade forum too, and read all 15 pages, but didn't find an answer to my particular problem.

The shocks leaked quite a while ago and my wife didn't bother to tell that the compressor had been running a lot, until the compressor finally stopped. I replaced the shocks, but waited a few months to get the compressor. Installed the compressor last weekend, but it doesn't start up. I benched tested the compressor, so I know it's good. I get power to the red wire at the compressor plug (with red relay wires jumped), but no ground at the black wire. If I jump the black wire to chassis ground, (with the red relay wires jumped), the compressor will work and fill up the shocks.

I checked the relay and it works. I have constant power to one red wire and power to the brown wire with key on. Blue wire does not have ground. I tried jumping the two red wires, but the compressor does not come on, unless I jump the ground at the compressor.

What would cause my loss of ground? One thread suggested the SCM was bad, but that seems unlikely as it worked fine before the shock and compressor failed. What about the sensor on the drier? I used the Arnott compressor, which did not include a new dryer (I refilled the existing one). Does this drier sensor have any influence on the ground circuit? Is there a way to test it? What is it's function?

Another thread mentioned the exhaust valve. How would I test this?

I'm really struggling on this one and it's getting frustrating. Any suggestions on how to troubleshoot it? Any other reasons I would have no ground at the compressor or the relay? Could running the compressor until failure have hurt something else in the system?

Thanks!

jeff5295 · June 6, 2011

Made a little progress today. I took apart the large electrical connector behind the right rear tire and found the ground pin was dark and tarnished looking. I cleaned it up and recleaned the connector at the compressor and now I can jump the 2 red wires at the relay and the compressor will turn on. I filled up the shocks and got to a point where the exhaust valve opened up to deflate them a little.

With the relay plugged back in, the compressor will still not fire up on its own. I'm still not getting a ground signal on the blue wire at the relay.

I unhooked the load sensors and manually rotated them, but it didn't make a difference. I'm doubting both sensors failed at the same time, plus since the exhaust opened up, I'm guessing the sensors are OK.

Since I keep finding blackend terminals on the ground wires, I guess I need to keep tracing the harness back and check all the rest of the connectors.

If anyone has any suggestions, I'd like to hear them.

Thanks

Jeff