Non Rallye fuel gauge either full or empty

Hey Al ! Wayne from up here in Penetang..

Did you wiggle that float arm around while checking resistance? I'm suspecting in your hand the rheostat contact arm is scrubbing the windings and looks good and then you put it in the tank floating and it moves the arm enough so the contact arm isn't touching the windings.

Quick check, gauge showing empty.. you know you still have fuel so crawl under and take an ohm reading from sender stud to the sender face and see if it's infinity or somewhere in the 10 to 74 range it should be. Do the same from sender stud to frame to see if the tank/sender is actually grounded.