e 34 wiring

Does anyone know where to get a decent wiring scematic for an e 34. Tacho will not turn off with ignition and as a result is killing the battery. Central locking...JOY!...
Removing fuse 20 cures the problem but other than that I don't have a clue!

Try this site http://dl.bmworg.ru/book/haynes/

Cheers. Will give it a bash!