Usually on top of the tank. Not far from the water fill connection. Mine is located inside the coffee table between the recliners, right over the fresh water tank. Turn it on and it will present itself.
If you were to take a tour of any of the factories it would answer a lot of those "what the hell were thinking" questions. After the axles & some the wiring is installed the frame is flipped over & they start with the floor & floor covering, yep the carpet & vinyl are under the all the walls, then build up from there, all the interior walls are put before the exterior & NO ONE picks up any trash in between stations, whatever is left gets covered up.