[jclark003]

The regulator reads battery voltage and controls the alternator excitation by increasing or decreasing the field voltage. So the field wire is the regulator output signal that tells the alternator to increase or decrease voltage back to the battery.

I would test again however first make sure your batteries are not tied together (closed emergency interconnect switch) and that the battery charger and generator are not running. Check your battery bank voltage with both engines off, then start your port engine and check voltage again on whatever bank that alternator is connected to. You should see a rise from 12.2 or so volts to up around 14. If you don’t get proper charge voltage you probably have a bad regulator or alternator. To determine which you would need to check field voltage at alternator with engine running. No field voltage usually means regulator is bad or a wiring issue. Good luck