Why does the gas gauge not work?

Hello,

This could be due to a faulty fuel level sending unit.
The sending unit consists of a float that attaches to a resistor panel.
Over time the float can get stuck in a certain position, or the resistor can go bad and display incorrect fuel gauge reading.
The sending unit is part of the fuel pump assembly, located in the fuel tank.

I have attached diagrams below for your reference.

Let me know of any questions.
Thank you.

https://www.2carpros.com/articles/how-to-replace-an-electric-fuel-pump