im trying to find out what kind of electrial work this car needs. this a 1986 528e and this is what the owner says the car does:

The temp gage and the TAC must be on the same circuit they would quit working but if you thump the dash they would start working, must be a dirty or loose contact. Also there is a short in the Dome light and radio circuit they work but if you leave the fuse in it will drain the battery.

anyone have an idea? any replies are greatly appreciated.

Pull out the gauge cluster and see what's up. Be sure to make a note of which wires went where... there's a lot of them back there.
Good luck

how hard is it to take the cluster out? on my old e30 i didnt even try to take it out because it looked really hard and mine had an air bag so it was that much harder. and that short with the dome light and stereo that drains the battery? what could cause that?

thanks again everyone

IIRC, there are a couple screws going from the top of the cluster up into the dash and that's it. You won't be able to pull it out very far before the wires stop you though.
You could also drop the under dash panel to get a pretty good look at things. There is a screw on the side that you can only see with the door open, then there are a few screws pointing up into the dash.
As far as the short goes... I don't know what to tell you. You just gotta start looking through the the wires associated with the things that aren't working (you said the radio and dome light) and try to find a wire with the insulation worn off, or a loose connection. Also check the fuse box really well, the underside too. They can get too hot and melt/deform causing shorts.
Good luck

wow lots of very useful information! thanks a lot!