My fuel gauge reads full all the time.
I dropped the tank to look into this.
Removing the pump and reading the fuel pump sending unit when the arm is down (empty) it reads 8 ohms. When arm is raised it reads 100 ohms (full)
I beleive this to make sense.

With chasis connector unplugged the guage is above full.
With the connnector shorted between B and C conection it read 3/4 full.
Is my guage just bad? Is there any other ground to look for at the guage?
I have refreshed the grounding in the engine area for Renix tech stickys.

 

I can't help you with the resistance. I had a friend watch my gauge while I moved the float back and forth (with it out) and it worked like that. Also last year i saw a post where I guy talked of cleaning the contacts in there with alcohol. I never disassembled my sender so I'm not quite sure how that might go. Anyway like I said, out, mine would work the gauge. Hope that helps!

 

Ok , I just starting cleaning the contacts of the sending unit with a electrical cleaner and wire brush. Hooked the pump to the connector and magic the guage read empty.
I Was checking with my light tester. While movng the float arm the 12V feed wold dim and get bright. Thus cleaning all contacts on the sending unit. Now to get this sending unit back in the tank.