Gurus of electrikery, help please

[ATO]

I have a problem with the temp gauge not working on my 1.6td
It's not worked for a few weeks but has intermittantly worked for 10 mins a few days ago out of nowhere.
I've tried earthing the gauge through relay 43 socket, needle does not move - the gauge itself must be working as it worked intermittantly.
So I have just tried a long length of cable directly from the sender into the guage via the relay 43 socket and it blew no.1 fuse on contact - which is 15amp and going by the fuse box lid it is the fuse for the radiator fan! Anyone got any ideas!?

Ps the wiring is unmolested and hasn't been tampered with since the factory

[VWCamperfan]

Have you checked the connection behind the dashboard? Can become dirty/corroded or move causing no or intermittant connection.

[ATO]

Yes all the connectors are clean and the strip is clean