Originally Posted by emerydc8

I would start with the poly-v belt. If it slips even slightly, it may cause the a/c clutch to lock out. I don't know if it's supposed to reset automatically after this, but it has been my experience that the a/c will usually not work until you turn the engine off and restart it. If you have a code reader, you may see a DTC code 7 (poly-v belt slips) on the base module (socket 8). If you haven't changed the belt in a while, it may be a cheap fix.

Also, if you are in a really hot climate (like here in Arizona), the a/c pressure may exceed the limit and prevent the clutch from engaging. This has happened to me a few times in the hot summer where I have parked the car with ambient temperatures of 113 F and the under-hood temperature must have been incredibly high.

Also, I was told by a tech once that under really high temperatures, the pressure in the system can be so high--even with the engine off--that when you go to start the engine and engage the compressor it takes a lot of force just to initially get the compressor turning and it could cause the belt to slip and lock out.

Originally Posted by leathermang

I am going to go with a more basic guess...
Your throttle suctioning mechanism... sometimes the Txvalve...but in more complicated systems ( than my type One ) it may have other components...
is not cutting off the cooling of the evaporator at a high enough temperature... thus below freezing fins on the evaporator are freezing the moisture in the air on the fins.... and cutting off the cold air... until you leave it to melt off and start over....