2015 Puma fuel guage

The sending units are a WEMA a style unit and they are individually sized for each tanks dimensions. You would be better served to get the actual sender from Parts.

I have had issues with the fuel gauges on my 2017 Cougar.  I was lucky, in that I was able to run down the causes with a multimeter.  My problems were intermittent, sometimes the gauge worked, sometimes it didn’t.  I wound up manually connecting everything together with solder, shrink tubing over the top, etc. to make it all watertight.  That was 3 years ago and knock-on wood, they are still going strong.  I would use a meter to make sure you have current and a circuit.  Another way to pinpoint it would be to pull the butt connections on both tanks, and since the other tank works run a jumper from those wires to the other tank and then see if that side (per the smart craft and manual gauge is still working).  If the gauges still work accurately then you know it is the wiring going to the sender on that side has a break in it somewhere.  Electrical gremlins are sometimes a pain.