The fuel indicator float inside the fuel tank, also called just float or erroneously, fuel indicator, is in reality a fuel level sender.
It is apparently a really simple part, but it consists of a small system constituted of the float itself; the float arm articulated to an axle carrying a moving contact over a resistor; and the resistor inside a housing/flange. Its function is to convert the fuel level measurements inside the tank in suitable information to the instruments in the vehicle instrument panel.
Since a few years ago, it has suffered successive changes toward the objective of improving quality, durability, reliability and performance, or even motivated by innovations in the installation environment and correlated systems, such as, emission controls, affecting the tank internal space, and highly corrosive type fuels. This has ended up in assembling the fuel sender resistor in a completely sealed housing and change of resistor material in a very significative modification in the float arm configuration and the shape of the float itself.
In the other side, the quality and precision required by the instrument panel modern electronics, such as, Board Computers and the most advanced Centers of Information to the driver, have justified the need for this work, the definition of a methodology that would lead to more reliable and precise readings of the fuel sender unit inside the tank, shown during the development of the next topics.