Chevrolet Repair: Air Conditioning, coolent, pressure switch

Question
I have 1980 Corvette. Air conditioning not blowing cold. What do I need to check to be sure system is working before adding refrigerant? Then which refrigerant to buy and how to  do about adding?

Answer
Hi Ian... red tech has a kit you can buy and has full instructions on how to install it...does compressor run when you turn on A/C if it does you should be ok... if not check for power at the plug. if really low on coolent it may not come on as it has a low pressure switch to shut it down so it won't be damaged...check for power at the switch, it is located in the low pressure line...you can by pass the switch as you need compressor to come on in order to fill system. put in the leak sealant first...once you have some coolent in then you can un bypass the switch and finnish filling...follow intructions with the kit...it works well....hope this helps