Hi, my new to me 94 940 sedans gas gauge reads empty all the time.
What is the most likely suspect and how do I trouble-shoot it? Can anybody
post some wiring diagrams for me please?

Most of the ones I have seen have been a bad sending unit in the tank.

"Tech" posted before that
it could be sending unit in tank. Well its been working on/off and this AM
while it was working I gave the dash a slight whack. Well it quit working and
at the moment will not work again. So I suspect some sort of wiring or possibly
a gauge issue. How do you get the dash out or reseat the suspected connector?

Any recomendations for a service manual to use?

As an aside, I had a problem with a clogged exhaust. So I assumed the CAT.
The 3 bolts and flanges were quite rusty so I needed to cut the bolts as not much was
left. To make a long storey short, the cat was fine, and the muffler(s) was rotted and
clogged. Had to heat the heck out of the bolts on the CAT flange to get them off as
it turns out they are studs. The flanges are quite rotted but currently holding fine.
Is there a source to buy new flanges?

Also I bought a Arvin exhaust. Nothing fit well. The first muffler pipe was 2 1/2" going
into the 2 1/8" cat pipe. checked several times and the numbers were correct for the
application. Reducers solved the problem. Anybody have a clue why the pipe diameters
were so far off?

Cheers, Dave

Well, the issue is in the dash. I pulled the dash and reseated all the
connectors. Worked fine until I snapped the bezel back in, then it quit.
Whacked the dash and it worked again. checked for loose screws,
connections, etc with no luck. Must be bad gauge or the circuitry that
drives it.