Fuel Gauge Wrong

[TexasAggie09]

I filled up my front tank today (rear is full) and switched to my rear. Everything was fine until I switched to my front tank again. The fuel indicator went waaaaay past full (see pic below). Switching back to rear tank and it goes back down to the normal level. Anyone have any idea what happened? Did my sending unit come loose or something? Where exactly is it located? Thanks yall.

[Nelson2011]

Hmm mine passes the Full line when i fill it, but not that much.

[CHUCK]

the sending unit is in the tank. Mines off on the E side, It'll read E, I'll fill it up, and only add 7-8 gallons.

[bucwheat]

Mine was doing crazy things like that and I added a bottle of Seafoam to each tank and it fixed the problem.

[planoguy]

My Front one did that. I dropped the tank and removed the sender. I've had some experience with other senders for various cars. I was surprised to see that the Ford Diesel Sender in my F250 was pretty easy to disassemble and CLEAN with a tooth brush and small pick. I scratch cleaned the Board that the Float makes contact with. Carb Cleaner helps too.

Put her all back together and works like a new one. I still need to perform this task for the rear tank. Also Clean out the tank while you have it down. Purchase the proper Fuel disconnect tools from Harbor Freight or else where to make this portion easy.