a/c not working

[94mitz]

I just started driving my truck after it sitting for about 2 years. The a/c is not blowing cold. The button on the dash dosent turn on the compressor, but I can jump the wire at the compressor to make it enguage and it does spin when the engine is running. Where would you look next? Low on freon? If so, has anyone tried the r12a in our trucks?

[royster]

Do not act with only my information, as I'm not an a/c expert. But the primary thing to be aware of is the need for the compressor to have sufficient oil. So don't keep testing it or running it until you get compressor oil in it.

The old refrigerant needs to be removed, and oil added to the compressor. It is my understanding that the various refrigerants are not crucial insomuch as the oil. Also, the seals ("o" rings) for fittings might be deteriorted after 2 years of sitting, so you might have leaks. Complete o-rings kits are available. Likely you'll want to flush the system out and check for any rust. There are a number of components that may need replacing, once you open the system up.

Though it isn't rocket science, air conditioning work takes some knowing, and to "convert" a system to the presently-used refrigerants primarily mean flushing the system out. So removing the compressor and inspecting it requires having the gaskets and o-rings to put it back.

[94mitz]

Ive only tested it twice to make sure it spun, and to see if it would get cold for no more than a minute at a time. In the next few weeks ill look at opening up the ac system to see what im working with. Just wanted to get an idea on where to start.

[royster]

You can look around the engine compartment to see if there is a rating for the refrigerant. I'm told freon IS still available, but "you have to know someone".

Also, there sounds like a problem with the switch or the fuse. I don't know that there is a relay that disables the a/c unit if the refrigerant levels are low.

Just wanted to get an idea on where to start.

And just wanted to offer a response :) The information I have is derived from rebuilding the a/c in my F-150, but the basic fundamentals are there.

[94mitz]

Thanks for the help. Ive checked all fuses to make sure they were all good. As far as the relay goes, I dono either. Need to look at the haynes wirring digram to see if theres anything when I get home. unless someone else here knows before I get home.

[meandmit]

I would make sure you have freon, that low/high pressure switch keeps it from switching on. On my '95 I have the small black box under the dash? It's under the glove box seen from passenger seat area. Sometimes the circuit board is at fault.

[bobbyk]

more than likely your low on refrigerant. because when your powering the compressor manually your bypassing the switch. you can always go to pep boys and get a can of quick fix refrigerant than look for leaks. try spraying the connections with soapy water if you cant hear the leak.

[94mitz]

meandmit- Ive replaced that little box already that your talking about.

Im going to get some of that leak detector stuff just to see where its leaking. Then go from there. Next step will be the seals I hope....