Confusion may be creeping in. The wire off/wire to ground is just to test gauge. It does not mean the gauge will read the sender properly. Ohming the sender just proves it's 30 ohms and seems to move in conjunction with float arm. The test that Dads shows with it all hooked up is THE only test that will prove sender arm down , gauge reads empty. Sender arm half way, gauge reads half. Sender up, gauge reads full. If a person can do this on the bench, as Dads shows and advises, then a person can move towards actual truck wiring/grounding issues because he knows it all works in the "lab". If it does not work on the bench, you need to leave it there and take the advise regarding bending, runtz or replace parts. Can you state that you have done the "lab" test so you can get back to a basic beginning? If it works on the bench with a 12 power supply and no resistor, then install it that way. The folks that have a gauge mounted and a sender in a tank which is mounted have much more trouble figuring out the gauge thing than those who can lab test. Maybe we are used to helping the installed fellow and don't realize you have the lab option. The original gauge/sender system is semi inaccurate, bouncy, sticky and not "real time" sometimes. If you dwell too much on making it work like a 2015 Chevy, you will go crazy, loose sleep, feet will swell and you will switch to hard liquor.
