The fuel gauge indicates no fuel when the tank is full. The float may have come loose from the arm in the fuel-sending unit, which has caused the rest of the components in the unit to come to a complete stop. This would cause the fuel gauge only to read "empty." A defective resistor can sometimes cause the gauge to read empty by limiting the signal to the point where it is no longer detectable. Wires that have corroded, particularly those that are part of a fuel-sending unit mounted on the gasoline pump, have the potential to interrupt the flow of voltage from the source or to the fuel gauge.