Well...finally got fuel gauge to work but backwards...have completed every test on this site that has been addressed. In the last trial i took everything out of truck..gauge and sender...worked fine. I put the gauge cluster back in truck and manually moved sender up and down and it worked!! Put sender back in tank and read half full which was correct. After patting myself on the back I turned the key off and gauge went to full!!!! Turned key off and the gauge never moved. Pulled sender back out. Key on, all worked fine...sender back in tank ...read half full...turned key off and gauge moved to full and won’t come back. Tank is grounded, cluster is grounded, gauge is grounded.. can remove sending wire with key on and gauge will show past full as it should..put wire back on and it goes to full and stays there whether key on or off...checked the key switch and all good. As stated several times before ...will work fine on bench test but not in truck. I’m giving up and going to start work on my bed wood...if anyone can think of anything I might try or tast let me know...time for Super Bowl ! Go Chiefs!
How was sender grounded during this out of tank test? I see you said you grounded sender to neg batt post. Was that wire to the sender flange metal?
Red: It's not the tank that needs grounded, it's the SENDER! that needs grounded from one of it's mounting screws. You say you put gauge back in truck and you kept sender out and Moved it up and down and it worked. During that test sender was grounded to battery negative. Then you installed sender and it does not work. That means sender is not grounded to the frame of truck. You need a wire from sender flange screw to frame of truck. Grounding the tank will not do it.
The sender has a gasket, the tank has cushions, the straps can have rubber under them. So all of it is isolated from ground mostly and the sender's ground gets lost and is relying on it's screw threads. Put a wire under one the screw heads and other end of wire to a good ground bolt on frame. Clean metal both places, no rust, no dirt, no paint at those points.
I don't know what you meant when you said you found a glass/bezel problem. Sounds fishy, what was wrong? are you sure you fixed that?
Gauge should have sender wire on the full side terminal and the power to the empty side terminal.
