I have the same issue with my 2022 Mule Pro FX. I haven't had time to research it yet so, if you get an answer, let me know.

 

Are either/both still in warranty? If so, I would have your dealer involved.

 

Okay, I finally got a chance to look at mine. I pulled the seat to find that the mice had chewed one of the wires to the gage from the tank. I spliced in a new wire and it all works great. Pull your seat and look at the connections to the tank, it is a plug on top of the tank, check the wires.

Bob