United States of whatever.
I had a fault with my sender unit, or so I thought. Turns out that the float had become saturated, it sank in the fuel showing empty all the time. I got hold of a new float and using some telephone jumper wire, managed to attach the new float to the sender arm.
If yours is playing up, remove it, re connect and turn the ignition on, move the float with your hand and see if the gauge works, if it does its the float at fault.