I just bought a 2005 Chevy Silverado 1500 LS Crew Cab. If I have it set on defrost and floor I can adjust the temperature of the air coming out. If I set it to blow out the vents on the dash, it always blows hot regardless of temp setting. If anyone has insight as to what the heck is going on and is willing to share their knowledge that would be greatly appreciated. In the meantime I bought a Chilton manual to read up on how the system works. Thanks