A/C help needed
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Joined: Apr 2000
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From: Houston,Texas
A/C help needed
I have a 99 C5. The A/C system blows very cold but the compressor will suddenly disengage after driving approx. 10 minutes.. After another 10 minutes or so, the compressor will resume turning and the A/C works fine. The problem has been intermittent, but has gotten progressively worse. The system is still fully charged with the factory fill of R134. I would assume the problem is electrical, since the system works so well when the compressor is turning. Any help would be appreciated. Thanks.
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Joined: Dec 1999
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
My guess is that you are slightly LOW on freon. The suction side of the pump operates at 22-27 psi. If the load on the system is high and the low side pressure is a bit low, the suction side can drop low and the pressuer transducer will signal the BCM to shut the compressor off until the pressure comes back up above the cut off pressure.
You will need a set of R-134 gauges to check the discharge and suction pressures.
Why do you thing that the systen is fully charged??
Bill C
You will need a set of R-134 gauges to check the discharge and suction pressures.
Why do you thing that the systen is fully charged??
Bill C
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
WOW!! That is way too high!! I JUST looked at the GM AC System Performance Test and the highest pressure recorded at 80% humidity, 1000 RPM, and an ambinate outside air temp of 110 deg is 32 PSI! The HIGH side should read 264 at the same conditions. The AC fan should be on high with both doors open while conducting the test.
Did anyone try to charge your system?? Give me a set of conditions and I will give you the pressures that your suppose to read.
Bill C
Did anyone try to charge your system?? Give me a set of conditions and I will give you the pressures that your suppose to read.
Bill C
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Joined: Apr 2000
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From: Houston,Texas
135,000 miles and the system has never been charged or had any service of any kind. My first thought was the system may be low, but that does not appear to be the case. The system works great until the compressor disengages. Maybe a high pressure cutoff switch is doing its job???
