How does the dashboard indicate when running out of fuel?

[DelMaddox]

When running out of fuel, the fuel warning light on the car dashboard will illuminate. There are two main factors that trigger the fuel indicator light: 1. Fuel level position: The float sensor transmits this information through simple liquid level position determination, which is also somewhat related to the shape of the fuel tank, though this aspect doesn't vary significantly across different vehicle models. 2. Recent average fuel consumption: This is primarily a standard considered by the ECU. If driving in urban areas with frequent stops and starts resulting in higher average fuel consumption, the indicator light will illuminate earlier; during highway driving with lower average fuel consumption, the light will come on later. This represents a relatively user-friendly design, though some vehicles may not be equipped with this feature.