AC compressor does not work

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M6 Dream
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Joined: Wed Oct 05, 2016 7:42 am
Location: Poland

AC compressor does not work

Post by M6 Dream »

It used to work but now after I refill the gas it appeared that in case AC button put to "on" fan starts to work but compressor is not working. I have checked directly with power to compressor and then cluch start the compressor. What happened as I was not modifying any wirings over last time. It is M6 87 with dual AC
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86_6series
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Re: AC compressor does not work

Post by 86_6series »

I would think, if the compressor was working before the need to add freon, it's
over or under filled.
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M6 Dream
Posts: 9
Joined: Wed Oct 05, 2016 7:42 am
Location: Poland

Re: AC compressor does not work

Post by M6 Dream »

I will check the preassure but as I said in case I put 12V to cluch directly compressor starts and working. I cannot start compressor by pressing AC button at the dash
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dwcains
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Re: AC compressor does not work

Post by dwcains »

As mentioned, you need to check the refrigerant level in the system, but also the function of the pressure switch on the drier. This page will give you an outline of the electrical system diagram:

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If you want to view and search the entire manual:

https://www.bmwtechinfo.com/repair/main/631en/index.htm
Dean
Lutz, FL

'85 635 CSi Euro #9402254
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M6 Dream
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Location: Poland

Re: AC compressor does not work

Post by M6 Dream »

Thanks for advice. When i was checking the temprature control sensor in the evaporator [behind radio in central console] It appeared that previous verification I had been doing at the outside temperature below +10 Celcius but still over +5 Celcius degree. It appeared that when I keep the sensor by fingers, after a while [5 seconds] signal is initiated and compressor clutch is activated. I assume that when outside temperature will rise, say to 20 Celcius degree what influence also temperature in the evaporator, after pressing AC button, compressor clutch initiate cooling with AC system. Is my assumption correct? In general I was at the point that in case outside temperature is over 5 Celcius degree compressor will start. Now I see that 5Celcius degree factor [even expressed in service manual] is separate thing, but evaporator temperature control is puting the compressor clutch at the 71 F degree ie 21 Celcius degree. If the parameters of the sensor in the evaporator is correct [ signal to comp clutch at 21C [71 F] by pressing AC button while the outside temperature is over 5 Celcius and below 21 Celcius ac fans will work but will not be supported by Compressor but just by fresh air

I think I present it in a very complicated way but prior to any changing of the evaporator temperature sensor I would like to know logic of the system in this regard

Thanks in advance for help
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