Fuel Gauge (yes I know... again) test results - confirm I am on right track

[Zshowket]

1970 Challenger, rally dash.
Fuel gauge reads 7/8, installed new tank, new sending unit, gauge still reads 7/8.  Disconnected the sending unit, no change to level.  Grounded sending wire, gauge did not move. Disconnected sending unit at gauge still at 7/8 tank.  Bad gauge?  All I got.  Comments or thoughts?  Bringing the card back to life after she has been sitting for 30 years.

[Brads70]

Check to voltage regulator.
https://forum.e-bodies.org/electrical-and-audio/11/quad-gauge-rallye-dash-no-readings/7233/

[Zshowket]

Check to voltage regulator.
https://forum.e-bodies.org/electrical-and-audio/11/quad-gauge-rallye-dash-no-readings/7233/

Ah, I failed to mention that Water Temp, and Oil function properly.  Ampmeter is bypassed.

[Katfish]

 Sure sounds like it's the gauge.
To be sure you could apply ground right at the gauge to rule out wiring from tank to gauge

[Zshowket]

I think I found the problem.  At some point the needle tried to exit stage left!  I guess it gauge grounded at some point and bounced so hard it bent the needle.  So I replace the gauge, along with all the others, and in 1 swoop I now have full gauge operation.  Prior I had no tach, fuel gauge or clock, but now, look out!