oil gauge not working?

this can be caused by a faulty sender or the oil pump pick up is clogged let try the oil pressure sensor first here is the the location so you can change it out. If this doesn't work you will need to drop the pan and clean the pickup. Check out the diagrams (Below). Let us know what happens and please upload pictures or videos of the problem.

If you are not experiencing any drivability issues it is likely a bad sensor, loose connection to the sensor or corroded connector, it can also be a faulty gauge.
Visually inspect the connector to the sensor. Make sure it is clean and secured.

I have attached the testing procedure for the gauge (look below).

It will also be a good idea to test the oil pressure, in case there is indeed an issue.
This can be done by attaching an oil pressure test gauge to the pressure sensor port.
With the engine at operating temperature this engine should have 40-60 PSI of oil pressure at 2,500 RPMs.

https://www.2carpros.com/articles/high-or-low-engine-oil-pressure

Please let me know of any questions.
Thank you.