Gas guage problems

[Chorner72]

I don’t mean to hijack this post, but I have a 1972 C15 and my gas gauge sits around 1/4 all the time. I can ground it out and the gauge moves as it should. I changed the sending unit last year and replaced my printed circuit on the back of the cluster. Still the same issues persists. Leads me to believe the resistor on the back of the gauge is the culprit. Where can a guy find a new resistor to buy? After reading this thread I can figure out what else the problem could be I am fairly certain you can only install the sending unit one way in these tanks, so I doubt the float is getting hung up. And help or suggestions are appreciated for where I can find a new resistor or if maybe that is not the problem. Thanks everyone.