Your in cab tank sending unit needs go be grounded to the cab in order to work properly. In addition, you cab needs to be grounded the to frame and the engine. I would check your grounds.
Looking back at you past posts, you have a ‘48 with a newer cab and had both a frame mounted tank and cab mounted tank. Do you still have both tanks? If so, do you have gauges for both tanks?
Last edited by Phak1; 05/24/2021 2:23 PM.
