Originally Posted by JDP
Where is the furnace access?
Find the furnace exhaust opening on the outside of the trailer. You can do this by process of elimination. IOW, it is not the refrig nor the water heater, it must be the furnace.
On newer trailers, often they do not provide any outside access. You might have to remove some panels on the inside of the trailer. If I remember correctly, mine is under the refrigerator.