When ignition is turned on, Fuel Guage goes to full and stays there, regardless of how much is in the tank. Pulled connector on Fuel gauge pickup (under rear seat cushion), according to the Honda Service Manual sender is OK. One wire goes to good ground, but the other has +12 volts on it, even with ignition turned off! Sounds like a crossed wire, but where?

Has anyone had this problem? Does anyone know how this gauge works? The manual doesn't give me a clue.

 

Did you do anything to alter it? If not, I'd take it back to the dealer to have them take a look. It should be under warranty unless you modified it.

 

I had the same problem once.
Is the floater in the sending unit.
It works just like it does on your toilet water tank , it goes up when is full and down when empty.
More likely it got stock on the full possition the lever is to close to the pump harness and it does sticks some times.
My suggestion is to take it to the dealer for service if is under warranty.
There should be no problem if you modified as long ans the mod had nothing to do with the fuel tank such a fuel pump or so.
Just don't take it to the dealer where you bought the car cause they may want to be a holes and give you a hard time if you modified other stuff.
It will be a good excuse for them not to work on your car if you have further problems