There was a recent discussion on RV net regarding causes of refrigerator failure. According to one operator of a rebuild shop, the largest cause of failure to the cooling unit is due to corrosion on the cool side of the coils from the outside in, due to moisture condensate.
Sorry I don't have a link for this.
There was no mention on how to minimize the corrosion. Perhaps shutting it off and leaving the door open could stimulate more air circulation in this insulated area and promote quicker evaporation of the moisture.