My 1999 chevy silverado 1500 ac won't blow cold airit seems like the ac/heater control module won't switch over and its stuck on heater.i already had it charged with freon.is this module costly and how much trouble is taking the dash apartto install a new one if thats what I need? lmk thx Rob

Number one you didn't get Freon in your charge. So if you paid for Freon which is super expensive you got ripped off. It takes r134. And just cause you. Charged the system did you have the system tested. If not tested by a good hvac shop you may have clogged filters or other issues including your bad controls. Also it may have leaked out again if there is a leak