Gas gauge not going down

Hey Everyone, I couldn't find any other post about this but my gas gauge doesn't seem to work. I first noticed this when my gas gauge wasn't going down even after driving around town. I pulled off and filled up around 25 dollars of gas, and when I turned on the truck it read the exact same. As I drove the truck back home it slowly went up(slightly), to the current position its in. Any ideas to what's the problem. Is it the bobber on the fuel pump being stuck or would it be anything else? I have attached a picture with where it is currently lies.

 

bad sending unit

 

Yeah, most likely a bad sending unit or float.
You can test it.

OP.

Start here. Grab the file uploaded by Dm93
And read on, we provided all the diagrams and “easy” access further down the thread.
Read the whole thing.
https://www.tacomaworld.com/threads/gas-gage-on-dash-shows-empty.729840/#post-26002388