The fuel sensor in a Proton Wira is located inside the fuel tank. It is attached to the fuel pump assembly and is responsible for measuring the amount of fuel in the tank. The fuel sensor uses a float and a potentiometer to determine the fuel level. The float is connected to a lever arm that moves the potentiometer wiper. As the fuel level drops, the float moves down and the potentiometer wiper moves along the resistance track, changing the resistance between the terminals. This change in resistance is sent to the fuel gauge on the instrument panel, which displays the fuel level.