AC compressor doesn't spin
 

964.

There's no freon in the system at all. It's leaked out long ago. I didn't use it in that state though. I want to fill her back up with some stop leak and refill it but I can't as it won't spin.

It worked before. Do they have trouble coming on when empty, and if so what do I do?

If the system have a pressure switch, you will need to jump the cables to activated the compressor. If not have a pressure switch, take the cable that exits from the compressor (I think is black color) and jump it to a 12 volt souce. You can take the energy from the rear engine fuse blocks.

If you want to fill the system, you need to make a good vaccum. Then recharge with refrigerant. Never turn on the compressor with the system in vaccum or you will damage it.

Good luck!!

The compressor should spin even when the system is empty.

If the clutch is spinning and does not lock in when you turn the AC on, the clutch, or clutch relay, is bad.

If the clutch engages and the belt squeals like a banshee, then the compressor is frozen.

Bad clutch is the most common.

This is only true if he doesn't have a high/low cut-off switch.

The clutch doesn't lock and that appears to the problem. I guess it appears as though the on switch isn't flipping on; so maybe the clutch is bad. I'll have to test the terminals for power when the switch is on. If I have current, then the clutch is bad. Thanks.

Last time I left it on for a while, farted around with it, and it started going...this time, no go.
Bummer...

Like nitro said, jump the clutch wires to a hot connection and see if it locks and spins the compressor. Just make sure its a beefy power source. On a 91 you probably have a hi-low pressure switch which has to be jumped if low on freon.

Black Death of a Compressor.

Non use and an open system equal frozen compressor which translate to BLACK DEATH

http://www.acsource.com/articles/bdeath.html

Thanks. I learn something new on this board every day!!

You want to use sealer and then recharge with refrigerant? Not a good idea, since the sealer clogs up the expansion valve, the reed valves in the compressor, and generally cause havoc in the system.

For more information, see the article at:
http://www.autoacforum.com/messageview.cfm?catid=20&threadid=9173