I have a 93chevy k1500.the entire ac sysrem has been replaced,it blows cold sometimes and blows cool othertimes. Why is that. The old system before replacement got so cold you could see youre breath on a 95 degree day.also you have to run on high speed with recirculate for ac to keep up all the time. If you run on normal it wont get cold only cool. I drive 50 miles to work it should be ice cold within a few miles of driving. Even the proffessionals are stumped.