Thanks for the responses.
First off, I thin my AC clutch plate and pully are ok as I am running the AC without problems and it is cooling the car.
Were does the power come into the controller (which pin)? My diagram shows the following pinout for the controller.
2. output to AC aux fan relay (coil #86) and compressor clutch
3. Input from AC fan switch
5. from AC temperature control ring
6. from AC temperature control ring
Thermistor may still be the culprit as I have not check its resistance. When I jumpered across 7 and 8 the compressor cycled
Tried applying 12vdc to pin 3 and compressor still cycled
When compressor was runing, I could cut it off and on by adjusting the temperature controller.
When compressor was cycled off, temperature controller had no affect.
All three blower speeds work correctly.
I currently have 12vdc applied to pin 2 as a stop gap and the system is working. Granted, I know I haven't solved the 'problem' but at least I have AC working until I do!
[FONT="Microsoft Sans Serif"]Don - 1984 Spider Veloce[/FONT]