the fuel guage on my wifes 67 gtx stopped working... the instrument panel was restored 2+yrs , and there is a new sending unit installed last year... what are the steps to find out what is wrong...thanks

Check ground between the sender and the fuel line to body. There should be a metal clip that bridges the rubber fuel line from the sender to the metal fuel line. This provides the ground to the sender unit.

Other than that, you should have a wire that plugs on a stud on the sender body. Make sure thats still connected.

if the temp gauge quit too, then check the voltage reg in the dash.

If the temp gauge works, then take a test light and attach it to the wire at the tank see if it blinks.

if it doesn't blink you have a break somewhere.

if it blinks then as said above check for grounding to the sending unit.

if that is good, then it is the sending unit.

Remove the sender power wire.Run a wire from the neg batt terminal to it.Turn on key.Gauge should go dead full.Just keep key on for a few seconds as you can burn it out if left on too long.That teast the whole circuit.I dont care for the ground strap from factory.I run a wire from the tank sender to the body and use a small hose clamp to keep it on the outlet.Rocky