Replacement Fuel Level Sensors
The fuel level sensor sends an electric signal to your fuel gauge. This sensor works like a float in your fuel tank to determine the amount of fuel contained within the fuel tank. In some vehicles, the fuel pump and fuel level sensor are combined into a single unit.
In your motor vehicle this fuel level sensor usually contains these components:
The sensing unit typically uses a float connected to a potentiometer. As the degree of fuel in the fuel tank is consumed, the float drops and slides a moving contact along the resistor. When the fuel level reaches a certain point, it will also turn on a low fuel light on some vehicles.
Meanwhile, the indicator unit is measuring and displaying the amount of electric current flowing through the sending unit. When the tank level is high and maximum current is flowing, the needle points to "F" indicating a full tank. When the tank is empty, and the least current is flowing, the needle points to "E" indicating an empty tank.