I might not be understanding the problem completely, but do know that old master switches can fail. Even the hardy 1-2-all switches sometimes reach the end of their life.
Even new master switches fail. One night sitting on anchor with a broken transmission, suddenly all the lights went out. A Blue Seas Dual Contact Plus, just fell apart sitting there. There we were no power, no lights in a roadstead anchorage, with the beer getting warm. Called Blue Seas and first they said sorry, then where can we send you a new one?
