fuel guage pegged on full, when empty

[freeride707]

ok so heres the deal
ever since ive gotten the truck the fuel guage has been stuck on full, sometimes it will move a little bit but mostly stays at full(one time it went to empty and fuel light came on but slowly rose as i drove it), been relying on mileage and assuming i have a 30gal tank. but ive ran out of fuel twice now and i really need to figure this out.

i know its not the guage panel itself because i know the needle moves. shouldnt be the sender either because it would be stuck on empty right? is this a wiring issue or is it the fuel sender

[JSchuricht]

Sounds like a wire is open or shorted to ground. Start checking the wires for breaks.

[freeride707]

Alright I will check the harness from the tank

[raw109]

Float could be stuck. My dad's truck had that happen when he put too much fuel in it and for whatever reason the float got stuck. Had to drop the tank and open it up to release the float.

[freeride707]

Yea that's what I thought but that wouldn't explain why it moves on occasion. I've hit the side of the tank a few times and nothing

[coot1]

Mine does the same thing. Took the dash apart and checked all the connections. Couldn't find anything wrong with it but it started working ok when I put it back together. It worked for about a year. Now it is back to doing the same thing again.

[freeride707]

well i will drop the tank when the fuel gets a little lower and try to get it to work, im hoping its just the wiring because the sender is $300 and the guagepanel is $675

[JSchuricht]

Before you drop the tank, try ohming the wires with the tank full and empty to see if there is a difference. If the ohms change then your sender is working.

[freeride707]

which wires? there is a whole harness coming off the tank

[Elwood P Dowd]

I had the same problem and when I dropped the tank I found my float and the rod that its attached to just laying on the bottom. The sending unit is so simple and cheaply made that they should be free at the dealership and the fact that they want so much for them blows my mind. If you do drop the tank and find out its the sending unit its pretty easy to put back together just make sure you spread out the piece of metal that makes the actual contact between the float assembly and the sending unit so it makes good contact. I dont have any pics and its hard to explain but the piece that I'm talking about is not much thicker than aluminum foil.