Ah right so it was that sensor simple things, big problems

Feel free to ask away if ever you need to (everyone else does )

You'll probably find the bulbs are gone, the EFI loom has the plug standard all MK4's have that plug (it is an EFI XR3i loom isn't it)

Yes, the blower switch, it will be black/red (the one in the MIDDLE as there are 2). The only circuit of concern really will be the illumination wiring as its very thin but if its a few gauges it will be fine.

There isn't an earth on the heater switch, as you probably know the car body is earth, so put a ring terminal on and screw it up somewhere, you will probably see the earth for the stereo wiring screwed up, or just use the earth in the illumination wiring at last resort