Hello. I have a 2003 Suburban 2500 Lt AutoRide with the 8.1 motor. It has the auto climate control both front and back. I hardly ever use the auto button on thermostat. when I have the air on in manual mode it blows out warm air but when I have the vent only on it blows out ice cold air. I am pretty sure that my A/C needs to be charged but to me the vent means warm outside air and the a/c means cold air not the other way around. I'm not sure if this is normal or what but never had a vehicle that worked like that. i'm not complaining or anything but was just curious. thanks