The blower motor works but blows hot air I've been told it's overcharged and if it is I don't know how to drain it. There's been no work done to the ac it just stopped blowing cold air about a year ago.

 

Was there work done on the A/C? Did it just start blowing hot air by it self with no one touching it? Please provide more information. If it was working and then just started blowing hot air then it can't be overcharged.

 

+1
the only way to tell if its overcharged is to either recovery the system and or check will manifold gauges. if neither was used...they are guessing.

 

it's really expensive to "get into" (get the tools you need). don't be an EPA enemy and vent R13 or R12 (both are bad) into the atmosphere. Just take it to a mechanic who has the expensive tools. often: a leak is actaully just a little o-ring that needs to be replaced.

you have to test if you have right pressures on high and low side. i can't explain the whole deal here (ie, the exchange value and what it should be doing).

NOTE: what MOST shops and people get WRONG is that oil level in the compressor is critical. too much or too little and it won't cool well or at all. SOME OF the machines pro shops use take more oil out than they put in during "normal service" and this eventually not only becomes "unfixable" (by re-doing the broken process) but damages the compressor too. that's the deal. if it's not leaked out R12 R13, it's likely the oil level

IT'S ILLEGAL IN THE USA AND ANY GOOD COUNTRY TO FILL THE R12 R13 WITHOUT FIXING THE LEAK %100 FIRST. it has to be tested at top torr (you need a pro vacuum) for minutes before you refill. it's the law. those damn auto stores selling those cans should be sued.

 

that being said, if it's not in the %95 of problems: it could be really complicated - something people can't walk you through.

HOWEVER i did forget to remind you: you know there's a mixing door under your dash right? if it doesn't move you'll have permanent head. sometimes it gets jammed it's just plastic gear there (don't force, you'll break and buy it right?)

I assume you checked if your refer lines are cold and they aren't. if they are - then surely it's your mixing door or temp control inside the cab.