If the inside of your camper is not heated, and you leave your refrigerator turned on, here's what will happen.
As long as the ambient temperature around the refrigerator stays warmer than the inside of the refrigerator, the refrigerator will continue to cool to it's set temperature. Including the freezer.
However, if the ambient temperature drops below the inside set temperature of the refrigerator, the refrigerator has no reason to turn on and keep things cool, as it's already cool. Ambient temperature will eventually be equal to the temperature inside the refrigerator. Once this happens, the refrigerator is NOT fighting the outside warmer temperature any longer. There is no need for it to run, and it won't.
What happens now?
Well, everything in the refrigerator will be cold! No doubt about that. In fact, the temperature inside the refrigerator could get as cold as the ambient temperature around it, if given enough time. That means there is no need for the refrigerator to run ... which means ... once the outside and inside temperatures reach somewhere between 40 degrees and freezing, the refrigerator is not running... which means ... the freezer is now thawing.
Depending on how long the ambient temperature hovers around the inside temperature of the refrigerator will drive how long anything in the freezer has a chance to thaw.
Once the ambient temperature reaches below 32 ( F ) (Freezing), the freezer section will then continue to freeze again. But by then, it's possible all your ice cream has already melted to a soupy mess and dripping everywhere.
And, if the ambient temperatures gets below freezing, the refrigerator section will begin to freeze also, and now you'll have frozen milk and eggs!
It took me a few years to figure this one out.
If you are going to leave your refrigerator running over the winter, the trailer has to be heated if you are in a climate where temperatures reach freezing or below. Otherwise, empty the refrigerator and freezer and turn it off.
Side note:
Have you ever wondered how Pepsi and Coke machines work? Have you ever used a Coke machine when it was zero degrees and the coke cans or bottles were not frozen?
That's because soft drink machines are built, not only with refrigeration in them, but also built with heaters in them, so if the ambient temperature reaches near 32 degrees ( F ), the heater will kick on, keeping them from freezing. It's true! Check with your Pepsi man the next time you see him!