Voltage Regultor Question

[Huckster FLHRC]

My next step will be gaining access to the back of the gauge check the connection and see if I can put the meter on it and compare reading.
May be awhile but I will add an update with what I find.

If you’re confident the battery is good, the next thing I would do, is put a volt/amp meter on voltage on the battery terminals,
checking the electrical system for a short or parasitic draw. Start pulling and reinstalling one fuse/circuit breaker at a time looking for a slight drop in voltage with everything off.