The first owner of our trailer [we are second owner] installed a fridge fan. Don't know where it was purchased or who installed it, but it works fabulously. The fridge fins never ice up and food is uniformly cold throughout. Fridge is Dometic 7cf, separate freezer door, two way [propane & 110v] set on 3. Ours run on propane [except when moving down the road] most of the time because we are addicted to boondocking. Freezer keeps ice cubes and ice cream frozen. Fan is
12v, has a switch if you want to turn it off to save battery if boondocking, but uses few amps. We wipe out the fridge to clean as needed, still have to defrost the freezer of course. We traveled from October to March [on our way home now] and defrosted the freezer once during our trip, in December. Turn the fridge off, leave the
fridge door closed, empty the contents of the
freezer into the sink, put a folded blanket over the frozen stuff. In about 30-45 minutes, frost is easily slid off the freezer walls gently with a plastic scraper and in to a plastic bin. Mop up the water and wipe the freezer as dry as you can. The walls of the freezer are still pretty cold at this point, put the still-frozen stuff back in. Turn the fridge back on. Done.
Picture of fan attached.