Cadillac Repair: 91 Deville Air Ride Adjustment, electrical schematics, air ride

Question
My 91 Deville has suddenly begun raising and lowering it's rear end.  Some days I come out and it's all jacked up...the next, it's lower but still higher than normal.  Any ideas on what I should be checking?  Common problem?

Answer
The problem is the HEIGHT SENSOR.

You will need, If necessary, Electrical schematics and picture locations of the components within the system that is causing you problems of which can't be done on this website which only allows one picture.  I do not have a website so you will have to e-mail: onlineautohelp@msn.com in order to obtain the information.