fuel always reads full

my neos fuel always reads full what could cause this problem before i spend money on things i dont need (batterys pretty f'd as told by previous owner)

 

Anyone?

 

faulty earth to the sender or fooked/bent sender

 

Ok how u check earth im poo with electrics.?

 

Does it read full when the engine is off?

 

My original though to the title of this thread was who "who would argue with that?!" , Haha.

 

lol no its digital so when bike off nothing shows anyway anymore thoughts