This is a photo of a small, about 1 1/2" piece of grey ducting that extends from below the floor (near the axle below, and water heater) into the space under the side gaucho in my '77 21' Globetrotter. Discovered after removing the gaucho as part of a renovation project. I cannot see any means of connection to the furnace, located on the opposite side of the trailer (furnace has been removed for replacement). Help identifying its purpose and origin/destination would be appreciated, as the service manual doesn't seem to provide any info.
Maybe it's just a crawlspace for rodents!