A/C recharge

You will have to go to a garage. R12 Freon is still in limited use but, you must have a Refrigeration Licence to purchase and use it. The disadvantage of it is that it costs somewhere in the range of $50 or so per pound.

It may cost about $1500 to retro fit with the 134a by the time you replace the compressor evaporator and condenser. But well worth it in the long run. Since it the 134a only costs about $6....

Here is a guide to help you charge the system

https://www.2carpros.com/articles/air-conditioner-how-to-add-freon

Please let us know if you need anything else to get the problem fixed.

Air Conditioning problem
1994 Chevy Truck V8 Two Wheel Drive Automatic

I trying to recharge the A/C on my chevy pick up how do I go about this ? Do I have it running with the A/c on while I use the A/c recharge can or off

Don't touch anything. You don't know how much refrigerant there is in the system. You need to take it to a shop to have it evacuated and recharged. You don't want to overcharge the system.

When AC is on Max Air blows fron floor vent as well as upper vent. Damper is not closing. It does close in the defrost mode. Is the Vacuum switch bad?

It could be. they did have a lot of problems with them. It could also be any of the vacuum actuators, lines or mode doors also so it need to be troubleshooted to find out.