The Outside RV Refrigerator Vent & Drain
On the outside of almost any RV of any type will be vents for your RV refrigerator. In the lower vent you’ll be able to see, usually, a small tube coming out of the vent. This tube is to drain “condensate” caused by people opening the refrigerator door and water vapor from the warmer room temperature air getting inside the fridge, then, well, condensing ( hence the word ) from vapor into water. If you let it build up, you’ll get a wet mess. Therefore, a drain exists to drain off the water. Sometimes ours gets iced up because its closest to the cooling elements. So it is important to check for ice and make sure you see a regular little drip outside.
The refrigerators themselves do put off heat so a vent to the outside is a good thing. Also the refrigerators can also refrigerate using LP gas in what is called a gas absorption mode of operation. For that a vent to the outside is probably even a better idea, just based on safety.
So, if you RV has a fridge, you should be able to find this vent and you should be able to find a drain tube somewhere. Here is a picture of one for you to reference :