fuel Guage error?

There is a fuel level sensor in the tank that sends a signal to the fuel gage. The sensor is easily changed without removing the tank. Typically it is mounted rough the top of the tank. There is a float which is attached to the end of an arm. The float moves up and down which causes the arm to move a slide wire resistor. Long story short, the slide wire occasionally goes bad and needs changed. Climb under the coach and see if you have access to the top of the tank. The sensor will be a round plate, screwed to the top. There will be a single wire attached to a screw in the center. It is a simole "remove and replace" but you will need to contact the factory for the correct part or you will have to pull it out and take it to a truck parts store