I keep popping the cigar fuse when I turn the ac on. I know I have a short somewhere in the ac system but have know idea where to start. Any ideas would be greatly appreciated.

 

Assuming this is an S5. A Blue/Black wire leaves the cigar fuse. The wire runs to the A/C relay. Before it reaches the relay the wire goes to connector G-02. This connector is located at the front nose of the car. It has the Blue/Black wire in addition to the Blue/Orange, Red/Yellow, Blue/Yellow and Blue/White wires. The Blue/Black wire continues from this connector and arrives at the relay. When the relay is closed the Blue/Black wire passes voltage to the Black/White wire which runs to the clutch. The relay is between the connector mentioned and the driver headlight. Besides the B/W, L/B wires it has a Red/Yellow and a Blue/White wire.

Your problem could be wire related or the relay or the clutch. You could possibly unplug the relay and do a resistance test on the Blue/Black wire. If it tests out okay then you could, w/the relay unplugged, jumper the Blue/Black wire to the B/W wire, which would bypass the relay. If the A/C works w/o blowing the cigar fuse then you have narrowed down the problem to the relay.