I have a 1997 GMC Sierra with 350. I can go out and crank it up and the AC will blow ice cold, for a long as I am moving or do not shut either the AC or the engine off. If I shut it off an then turn it on again the AC will blow warm air and get progressively hotter. It does not matter if I only drive 1 mile or 100 miles. I thought it may be freezing up, but it was not. I thought it may be a bit low on freon, so I bought a recharghe cyclier of freon, but then I noticed when this sudden stoppagage of cold air occurs the compresser is not turning. I figured its got to be low on freon and the pressure switch is keeping it from running. I wait and catch the system when it is working and hook up the charge cylinder and gage, but the system shows sufficient freon, so that should eliminate low freon as a problem.
When it does work its good and cold. I am at a loss.any ideas what to look for? Possibly a clogged dryer? Vehicle only has 50K on it. Taking it to a dealer is out of the question for now. Regards
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