Battery power lost to trailer.

facory wrote:
Battery voltage without park power is 13.0 - 13.3 volts. Voltage when plugged into park power 14.4 volts. The power panel has the positive battery lead on one side and the negative battery lead on the opposite side. The voltage reading there is only 2.3 volts. If the converter is charging the batteries through those same cables then I don't understand why the battery's voltage is not coming back through. My dilemma.

There is no diode in the circuit. Just copper, a fuse, switch and multiple connections that will conduct same in either direction.

If you measure 13 volts on the battery and 2 volts at the fuse panel you have a bad connection someplace or the readings are wrong. Yes very odd to consistently have same voltage when charging and 10 volt drop on battery power.