'89 DeVille ELC Sensor
 

The compressor will inflate the rear shocks when the test lead is grounded.

It will return to level when inflated above level.

The "Vehicle Leveling" light does not come on when the ignition is in "run".

I suspect the sensor is bad.

Where do I find a new one at a good price

It worked two times yesterday when my wife was driving it?

I now suspect the connector at the height sensor because I found the rubber boot over it to be loose.

I'll take the wheel off and have a better look after the holidays as it is almost impossible to access with the wheel on.