maybe the fuse connector then? it seems like everything you are describing somehow ties in to a piece linking all the malfunctioning parts. wouldn't a wire of some sort cause your fuse to blow? You said the fuse is still intact so it must be something else. when my tach, oil pressure, temp, and turn signals died it was because of an issue in the fuse box. I'm not disregarding what you have already said you did, just trying to throw out a simpler suggestion before you go into any extensive and unnecessary fixes.

__________________

1990 190E 3.0L