Dash cluster fuel gauge not working

[azsr20det]

So when i bought my S13 in 2010 the fuel gauge didnt read. I figured the float came off the arm so now that im finally working on the car almost a decade later I pulled the pump and sender out and the fuel float is infact attached. Heres a pic

https://i.imgur.com/Uw4wlkI.jpg

Any ideas why its not working? I bought an aftermarket fuel level sender and gauge but id really prefer to fix the stock unit before I go throwing aftermarket parts im there.

Any ideas?

[azsr20det]

Nobody has any idea where to start diag on this problem? Fuel systems and electronics are def not my forte :/

[azsr20det]

Nothing? The sender seems to be putting out the correct ohms but the dash cluster isnt adknowledging it

[teejayhoward]

Pull the cluster. Find the pin on the cluster that corresponds to the fuel gauge. Test the reading at that pin on the harness side. If you're getting the right reading, you have a bad cluster. If you're getting a wrong reading, you've got a short in your harness somewhere. Trace the cable back to each connector in between the cluster and the sensor, testing at each step. When the readings come out correct, you know where the fault is.

[gaz_moose]

how does the circuit work?? does it measure resistance to ground? if so I would just earth the plug out and see where the gauge goes. if it moves you know its good.