Need Advice: We Lost 12v power this Morning on my 4600 SCB!

[Moretoys]

Hey Guys, I'm needing help diagnosing a critical issue this morning. We're north of Jacksonville, 800 miles into delivering my new 1999 4600 SCB from Hampton to Marathon.
We went to bed last night at a mooring with everything working fine. We fired up the Gennie thIs AM and only saw one leg come up. A bit of on and off with the switches and it eventually came up on both legs, though the voltage was low: 90v rising to 103v as it ran. Somewhere in this process we lost our 12v to the house. It just went dark. The Engines crank, bilge pumps work, but House is dead. We show 12.51v on the two house/engine batteries in the engine compartment , and 14.1v on the Gen battery aft. We have no inverter installed. I've cycled the 12v Main beaker in the breaker panel.
IS THERE ANOTHER 12v house breaker somewhere?
Could this be related to the charger or isolators?
I HAVE to believe that this is somehow related to the Gennie issue: The odds of two completely unrelated electrical failures happening at the same time are high. Any suggestions or advice? GP