well the belt is always turning the outer part of the pulley, with or without the ac on... When you turn on the ac, the center section of the pulley is energized and locks itself to the spinning outer part. So if that center section is not turning with the outer pulley when you have your AC switched on, then you have a problem somewhere there. If it does turn with it, then that most likely isn't what that wire is for...

here's a vid of how the AC clutch works...

http://www.youtube.com/watch?v=kp8pXmlFq_w

 

Well the center doesn't turn.

 

But not the center section? If not, the compressor isn't running..... Generally, that indicates low charge. If it worked good, and then stopped..... I am going to guess you sprung a leak somewhere.

Got two choices, pay someone else to figger it out, or, go and buy a can or refrigerant, with the hose and GAUGE!!! setup, hook it up, and see what it says. If there is some pressure left, you might be able to shoot some more in there, and get your a/c back. If it is completely empty, don't bother shooting any in there..... It won't stay.