A/C wont start - checked _everything_!!

[NeoP]

Fellow TI-Owners,

it's been a while since my A/C got some special treatment as i wrote
"...my a/c stopped working the other day. Couple of frustrating tasks later i figured the fuse to be killed - worked with a replacement for a couple of weeks (i bought an automatic one, then ;-) ). Sadly, it jumped nearly every day the last months, not bothering me during the heavy bavarian winter...
After i figured that it was a spark going from the connector of the clutch at the pump i tried to check on this one, but guess what it was, after weeks of wondering and frustration? The cable going from the connector to the clutch, around a sharp edgy part of the pump. Everytime it touched the sharp metal of the pumps frame, it did a spark and killed the fuse. This cable is quite tiny and on the surface of the pump. You can see it when looking in from the top of the engine bay."
Well, a couple of days ago it suddenly did not cool anymore. Checking on it not being the same issue again: all fuses are okay, the fan is running, lights in dash are lit, car is warm, not too cold, since today it's completely serviced with a new cooling liquid r134a filling (160 grams to few of cooling stuff in it) so it is not leaking or so, but it won't start the compressor... Damn, can anybody help? This one really sucks.

TIA!