OP... The Problem is when I disconnect shore power, we have no 12V power. The battery voltage was tested on the battery terminals with nothing connected. The trailer wires were tested disconnected. This a TT and we are parked for the winter, so this will only be a problem for us in the short term if we loose park power which has happened in the past. We will get the batteries tested (they are over 2 years old) and pull and check the plastic auto type fuses above the circuit breakers. Thanks for the assistance and sorry if OP wasn't clearer!
