Ok. I press the auto button to "IN" position while I am conneted to a 30AMP power source and the fridge cools using AC/power. It will not work on battery only.
I press the auto button to the "OUT" position and the LP kicks in (you can hear the klicking) and cools the fridge. I use this option while travelling to keep fridge cool while on the road.
One thing I read on the manual is that the trailer must be leveled or else the fridge will not cool, it has something to do with the freon inside the aluminum canister.
See ya' out there.