[PeteChappers]

From the tests iv done trying to solve my AC issue.

The fuse you talk about is probably it, i would image all the air/climate system runs through that.

The only wiring to the compressor is the wiring for the clutch.
I had no voltage at first so electrically i tested every thing that i could find to do with it. - which was fine other then it not getting voltage when the button was pressed.
From what i gathered while checking it out this was because the system did not have any pressure/refrigerant in it. There was a sensor forcing it to stay off, to stop it damaging its self because it was empty of gas.

As your system is gassed, i would think that the sensor is faulty in your AC line if the fuse you are getting doesn't work. Also while messing about with it if my system was over gassed, the clutch would start up then stop again as the pressure was too much.

I think the sensor is the little black box located near the windscreen side of the bonnet attached to a steel pipe at the top of the engine bay.

Im an engineer but no car mechanic, this is only what iv figured out in the afternoon i was trying to repair my car. so its my best guess.