A/C question

[broke350]

Recharged the A/C in my 79 and it blew cold for a while in the driveway, hopped up on the highway to go grab a bite to eat, and within 10 minutes, blows warm air.  Tried it the following day just to see what would happen.  No recharge, just fired it up and kicked on the A/C. Blew cold for a  minute or so, then back to warm.  Any ideas on what to check?  Also, my blower motor never shuts off while the key is on.  If I turn it off, it just stays on the lowest setting. 

[jaredts]

With the a/c on does the compressor kick on and off rapidly (every couple of seconds)?  Does it kick on once and then never again?  What did you do to recharge it, just add a can or two or did you use a gage?  Has your a/c system worked recently or are you just trying to get it going?  I'm not an a/c guy so I can only help if its the simplest of things.

[Grim 82]

I think the fan is always supposed to run when the key is on, probably to keep the box and ducts dry.

[broke350]

It's been over a year since I've had A/C, I've just been driving it more and am starting to miss the A/C.  I just added a couple cans when I recharged it.  I'll have to go check it again to see if the compressor kicks on. 

[Irish_Alley]

if its been a while since you had a working ac it probably lost some Freon you have to find the leak and fix it.

[jaredts]

If its low on refrigerant it usually kicks the compressor on for a couple of seconds and then off repeatedly.  When you put a can in it starts to run longer until it has enough to operate normally.  If you find that its kicking off and on rapidly put in another can that has the dye in it.  If its a bad leak you won't need a black light to see the dye as it'll be all over your compressor or fittings or whatever is leaking.  I'm with Irish, it sounds like that's your problem.

[Layne]

Did you add too much? It's not freezing over?

[broke350]

I'm not sure if it was over filled.  It's been over a year since I charged it and this all happened.  I've swapped motors since then and put all the A/C stuff back on, but never put the belt back on because I knew the A/C didn't work and figured I'd have to replace parts but didn't know where to start.  I'll have to go find the belt and go from there.  Hoping it's just a leak somewhere.  Thanks for all the input guys!