Make sure it can be turned off , or to another mode like ac . Or the fan will run if the temp falls below the lowest temp setting .Or at least disconnect battery's when not used .
If your brackets on the camper are parallel to the side wall - most campers are - them the Swing Away`s wont give you 4" per side . they give you that much if the brackets are perpendicular to the side wall.They still give you more than a used set of...