Hopefully someone can help me out with this one. I start the car and turn the heat/AC selector from either off or heat to AC. No matter where I put it in the AC side, it will typically just blow warm air. I hear the comressor kicking on, my RPMs drop a tad just like normal, and everything seems normal. I figured that it was in need of a recharge. I put topped off with R-134A and it blew cold as could be...until I shut it off and turned it back on. Then I found that sometimes I would have to cycle the AC/heat selector **** back and forth several times for the AC to start to blow cold. Each time the compressor kicked on but it just blows hot air. Then after several cycles of the switch, the AC will blow cold again. Any ideas why this is happening? there is no binding or mechanical problems that are readily detectable. Any assistance would be greatly appreciated.

 

Check to make sure the cooling fan is coming on when the compressor comes on. it may take a minute or two the first time, but the fan should come on. If it doesn't you need to see if the cooling fan itself works. if it does, it probably needs a pressure transducer which is located on the high side a/c line