I have a 5th wheel with a residential refrigerator with ice maker and a dishwasher. Since I live near Houston, TX the weather seldom gets below freezing and I don't winterize other than draining wate...
That’s what I do. I keep heat in it all the time, leave the hot water heater on, cabinet doors open, commode lid up, and a small heater in the wet bay. Has worked for years.