How to turn off interior lights while driving

To the OP, there is nothing wrong or unusual about your RV. The refrigerator is supposed to switch to LP when it is the auto mode and no ac power is available from shore or generator power. It is true 12 volt dc power is required for the refrigerator control system but this nothing to do with the lights. The vehicles electrical system has nothing to do with providing ac power to the refrigerator in your case.

Don