fuel sending unit and fuel gauge trouble

wiggling the inst' cluster to make pulse voltage come and go that far out the circuit doesn't help much. You have to have the 12 volts into the limiter, then pulse out of it, and into the fuel gauge, and through the fuel gauge and down that length of wire to your test point. Any loose connection in that path ( pull the inst' panel! ) Also know that a digital volts meter doesn't report the pulse accurately but... any meter can report voltage present that isn't enough to operate the whatever. In this case you need enough current to generate heat in a resistor/thermal range indicator.
A pal nut is stamped from tin. It has a inner edge touching a single thread in a contact post. Then a outer edge with nearly no flange sitting on a contact pad of the board. Imagine a stranded wire with all but one or two of it's strands broken. Meter will show voltage but..., Enough current passing to operate anything aint happening ( unless the wire was waaaaay oversized. 1 stand of a battery cable will operate a dome lamp LOL ). Anyway... A loose pal nut is the same broken wire condition.
Many owners here in this forum have found this very same fault, 2 within the past week. Others of us answer the same questions over and over.
I wont go into why engineers choose to use pal nuts at these locations but used machine nuts and toothed washers at the amp gauge.
The limiter could be loose in its contacts too but those are heavy gauge male spades in springy females that absorb vibration. Anything is possible, just some things less likely.
What we can assume at this point... the limiter can operate, the resistor winding inside the fuel gauge is intact. Conductors that are actual wire are probably ok.