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      05-05-2021, 08:08 PM   #2
chipguy
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Drives: 12 528i
Join Date: Feb 2019
Location: san jose, ca

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Quote:
Originally Posted by mrvedit View Post
On the 2011 535i we just bought, the A/C cycles on and off every minute which prevents optimal cooling.
With engine running and A/C controls set to lowest temp, I put a pressure gauge on the low pressure side and it alternates from 25psi to 50 psi as the compressor cycles on and off. Its about 30 seconds on, then 30 seconds off. I tried different A/C settings, such as Max with re-circulation and just regular; it doesn't make much difference.
While not an A/C expert, the pressure indicates there is enough charge and the interior vent air temp of 40F when the compressor is running indicates it is mechanically sound.

Any ideas? Is there a possible pressure sensor malfunction? Hoping its not an A/C control unit.

My daughter has this car in Colorado - I'm just trying to give her some guidance. She will likely take it to an independent shop based on what you guys think.

Thanks.
You might actually have too much R134a in the system. If this is true, the high side pressure will be too high and the system will stop the compressor. Was there work done on the A/C? If so, who was doing it?
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