"Grounding the sender wire does not move gauge" is a very valuable start!
Does your temp gauge work?? They run off of the same 6v source (the little "voltage regulator" bolted to the back of your instrument panel)
If Yes then it sounds like the gas gauge itself is an open circuit. First I would make sure the
leads to the gauge were on it properly.
But I would also make sure the wire from the gauge to the trunk was not broken/open. I own a long pair of homemade jumpers for such tests. I assume you have a multimeter - all you need is resistance.
The gauge is easy to remove from the dash to work on - the bezel pulls off and the gauge is held on by 3 or 4 little Phillips screws. Make notes of what wire goes to what post. With the gauge dangling out in the open you can then use jumpers to ground it out, check for voltage to it, look for wires off and so on.
Worse case scenario: no continuity across the gauge. Then it is dead. Personally I would get another one on Ebay (59 and 60 both had white faces while 58 is black) although there are gauge guys out there who overhall these things (see Services in Hemmings)
At the trunk end, the unit needs to be grounded out properly to work and paint/rust/crap can prevent this. Five minutes of cleaning can fix this. As Jed says, its gotta float!
Basic attitude: take nothing for granted.
Basic goal: keep narrowing it down. Keep us posted!
Last edited by JohnG : 12-30-2008 at 08:08 AM.