Tail light and other electrical issues

Hi,

So my 3.0T 1994 SC has developed a number of electrical issues including tail lights which have stopped working, fuel low lamp, all dash backlights. Rev counter has also stopped working.

Have checked all fuses and everything seems ok.

Has coolbox etc but none of it seems to work.

Previous owner had wired new stereo in (very rough job!) but only connected front speakers (badly) so nothing in the rear works now and I cant find wiring from rear speaker in the dash now.

If anyone can offer advice and/or a wiring diagram for this model it would be awesome...

Cheers

BRD