So from what ive seen doing my searches is that there must be a short somewhere. Most likely in the sending unit but Im having trouble finding a new one. Ive checked the wiring and it all looks fine. does anyone know where to find a new sending unit?

 

Mine would work from full to half tank. I finally dropped the tank took the sending unit/float off and found it was slightly rusted where it pivots and seemed stiff. I took it apart cleaned it good and removed all the rust. After that the float pivoted freely and loose and now it works perfect! Try that before you buy one.