I was working on my 55 1st which is converted to a 12 volt this weekend. Assume the gas gauge is 6 volt as I never changed it. I took the following notes.

F post or post connected to sender

E post or post connected to ignition

Post to post resistance reads 29 ohms

F post to ground or outside of housing
27 ohms

E post to ground or outside of housing
57 ohms

Check for burnt or broken wires. Central rivet if loose can cause problem with the ground. Also need connectivity from housing to dash

Last edited by dcraven; 01/19/2015 3:47 PM.

Dan
55 Chevy 1st Series 1/2 Ton - 350/400 Hydra