Re: 2001 f-250 5.4 liter. gas gauge stuck on full
It can be the sending unit. There's a yellow/white wire to the sending unit. If you ground it, the gauge goes to empty. If the wire is open, the gauge will go to full. The instrument module can also have a problem. Try grounding that wire from the sending unit and see if it coes to empty. If it does, the sending unit is the problem or the black/orange isn't grounded good. There's a black wire on it that grounds the fuel pump and if it was bad, the truck wouldn't run.