Hello All, I'm a newbie on this site and I have a possible problem. My 2002 Silverado does not blow cool air with AC on until I get up to about 20 -25 mph. After that it works fine. If I have to sit for over a few minutes at idle, the warm air starts again. Then when I start moving it works fine. I've never had the AC checked as I have never had any problems with it until now. This is not a major problem, just an irritant. Any advice would be appreciated.