QuestionI'm not sure. Was going to pull over and check, but here's some additional info I found that I would think will have a bearing on your diagnosis. I have a 30 minute commute home from work in highway traffic. About 15 minutes into the trip, the cold air went away again. This time I left the selector in the AC position, to see if it would come back on its own in another 5-10 minutes. It never did. But by the time I got home, I could smell smoke coming from the engine compartment. When I pooped the hood, with the AC control still on and the engine running, the compressor was running and smoke was coming from the compressor. When I shut off the AC at the control panel, the compressor stopped running. I turned off the ignition and used some water to cool the compressor. About 2 hours later, I started up the car again, and turned on the AC. Under the hood the compressor beagn to run again, and cold air was flowing into the passenger compartment.
Now what?
If the system is low on freon, and the Low Pressure switch is what is causing the system to shut off, should the compressor still be running? Isn't the purpose of the low pressure switch to kill power to the compressor if the system is dangerously low on freon?
Does the freon (like lake water in a boat motor) cool the compressor itself? Might this be what caused the smoke, overheating/friction? Or do you think it might have been electrical in nature? The smoke was coming from between the clutch/pulley and the compressor.
Thanks for your help.
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Followup To
Question -
Problem started yesterday on my 95 Pontiac Bonneville. Did it again today. Cold air goes away after vehicle is running for about 5 minutes. Blower still works, just no cooling. About 5 minutes later, when I try it again for the 20th time, it'll start cooling again. No previous cooling issues. Does a low pressure switch act like this? Or is it all or nothing? What else would you recommend?
Answer -
Are the a/c lines under the hood freezing up to the point that frost can be seen on them when the compressor stops working ?.
AnswerOK, You found your problem. You have either a faulty:
A/C clutch assembly on the front of the compressor.
A weak magnetic coil that is behind the A/C pulley that energizes and magnetically pulls the clutch plate to the compressor plate in order to rotate the compressor internal components.
A worn out A/C belt that is slipping on the pulley when the compressor is engaged.
Without actually seeing this problem personally, I cannot give you an exact diagnosis.
