Auto leveling system from 1979.

[Adam Brodwolf]

Hello Everyone:
On my 79 Eldorado, the compressor will not run nor does the tell tale light come on for it on the dash.  Following the shop manual, the fuses are fine, and then connecting the yellow test wire to ground makes the tell tale light come on and the compressor runs just fine (pumps rear end up too).  Shop manual says repair open in ground circuit.  Where? Which ground circuit?  Please let me know if you might have had this same problem.  Thank you.
Adam

[Bruce Reynolds # 18992]

Gday Adam,

If you are in California, they are probably telling you to fill in all the cracks and holes in the ground from all the earthquakes.

But, seriously, you have an earthing problem with most likely a corroded earth joint or chassis attaching point.

I would be looking at the control valve at the diff, as a starting point, as this area is most likely to get attacked by road grime and the like.   Then trace the wiring back to the unit in the engine bay.

You might have to undo each joint, scratch a clean surface, and re-attach.   Electrical gremlins are so hard and frustrating to find, and earths to one thing can find their way from other components.   My Son has a 69 Olds 442, and it turned out that the earth was the gearshift inner cable, as all the other earths had become compromised, or were missing.   It eventually melted the outer cable and broke.   That is how we found it.

Bruce,
The Tassie Devil(le),
60 CDV

[Mike #19861]

 Refer to the circuit diagram for the system. While the 1979 manual is not as concise as those from the 80s, it should give a location of where to locate the ground.

 Normally, the wiring from the sensor in the back runs all the way to the front, and the circuit is grounded next the comressor motor, so you can start there.

 Also, by grounding this test wire, I believe you are by-passing the height sensor, and merely checking for compressor operation. If you can obtain a known good sensor and plug it in, you can further check the operation of the system. While you are back there, make sure the link is securely attached to the control arm. It is commom for them to break off and the system will not work.

  Mike