The fuel-sending unit is used to measure the amount of fuel in the fuel tank and communicate the fuel level to the fuel gauge on the vehicle dashboard. The most common problem that causes the fuel gauge to read incorrectly is a bad fuel-sending unit. The fuel-sending unit is used to measure the amount of fuel in the fuel tank and communicate the fuel level to the fuel gauge on the vehicle dashboard. This ensures that the driver is aware of the fuel level at all times, as well as warns when the vehicle is low on fuel, and when to visit a gas station before the tank is completely empty. If something happens to the fuel-sending unit, the fuel gauge is the first to show it, so let’s take a look at how the two work together.