whenever outdoor temps drop below 40f / 5c, regardless of whether the interior of the rig is heated, the cooling unit of the fridge is open to the outdoor temp.
It will stop operating when the temp around the outdoor coils drop below that threshhold.
To make an ammonia absorption fridge work in freezing weather you must keep the coils above the low temp thresh hold by keeping the cabinet warm.
Blocking the lower vent with tape or plastic ( that big door on the outside of your fridge) to some or all of it will do the job, as it raises the temp around the heat exchangers.
Downside is that it takes daily attention to adjust the amount of vent restriction to keep a warm , not too cold, not too hot temp around the coils.
So no, I say do not leave the fridge on if you are away more than a day in cold weather.