If you ground the sending unit terminal of the gas gauge directly, what does the gauge do? If you add a resistance between 0 and 90 ohms what does the gauge do? If nothing, check for power at the printed circuit trace. If power is good, then your gauge is not. The coil is visible from the back of the gauge, check for a burned appearance or a visibly broken coil wire.
Vikki 1969 Goldenrod Yellow / black 400 convertible numbers matching