A/C control unit 20 pin info / schematics

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Miro I meant to thank you for your hints and insistence on diagnosis first. I would have gone down the same route but good to know sanity checks from someone else esp in the forum.

Y'know a really good thing about diagnosis is that in the end your mech will also be wiser for future support on your car too.

The Delphi Diavia tech manager was also instrumental and he really kept me informed and also hope! I have fedback results of the diagnosis to him and he hasnt shyed from commenting on it with more hints and some very perceptive remarks about condition of components based on symptoms.

I found out from Andy mine is a Harrison variable displacement compressor with mechanical control valve internal into the rear of the compressor. Being variable, it has no thermostat so when AC is on, it spins continously. My mech found out surprisingly that my AC doesn't go below 14 deg C. Andy confirmed mine should go to 4 deg C like other cars. To this finding he said the low pressure should after 5 mins operation be constant at 2 bar. He did alert in variable disp compressors this is often difficult to check. And also the valve that controls the variable displacement is held into the rear of the compressor and can be replaced (I need to check into this). He did say if the mechanical control valve is faulty the pressure would be not be 2 bar ie either higher or lower than 2 bar. Also to check duovalves working else hot heater is compromising AC cooling (is there any other neat ways I can check this without opening the duovalve? ie stick thermometer into heater matrix - can I easily access in there?)

I mentioned in the past there were 2 occasions where during extreme hot weather and continous AC use, it would switch off during which I cannot switch it back ON until a certain period had passed. He said this was the water switch (near the drier) which is set to switch off the AC when coolant temperature reaches 100 deg C. (I've read others have had this occur - well this is the explaination)
 
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