What causes the AC Control Unit to keep failing?

[Spades]

Has anyone gone in depth to repair their AC control unit (ECU) and to find out what is causing them to fail? I had mine fail a few months ago and I just bought a good used one from someone else and it worked for about 20 minutes and failed again. Id like to find a schematic showing the pinouts of the unit so i can see what components are being driven by this control unit. And what does the adjustment screw control

Here is a pic of the control unit

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[luv2rallye]

Haven't repaired one but from the diagram I can see that if there was a short to ground in the green-orange wire, it would burn up its output transistor. Don't know what the adjustment screw controls - perhaps temp turn on value or temp hysteresis. Sorry but with images limited to 700 x 700 pixels it is a little blurry with all its detail. Pm me with your email address if you need a little clearer image.

 

[Spades]

Hmm, my AC control unit has a 12-pin & a 6-pin all combined into 1 harness but in the diagragm i see only 5 pins being used. PMing you with my address for that higher res version, I just printed it and it was this little 2.5 x 1.5 image

Is the "Fin Thermo Sensor" the same as the expansion valve? And if so, does it OUTPUT to the AC control so that the AC control can cut-off power to the compressor? Or is it the other way around in that the AC control sends a signal to open /close the expansion valve?

 

[luv2rallye]

No they are not the same. The FIN thermo sensor measures evaporator input air temp to turn on/off compressor. The expansion valve is used to control refrigerant flow into the evaporator. See: AUTO REPAIR HELP - AC EXPANSION VALVE