When you open the door to the camper, in the right-hand corner , under the upholstery fabric that hangs down, there is a little switch. I think it is white in color. It is just a simple little push in and out thing that closes when you drop the roof. Mine was stuck also. All that was required to fix it was to push it in and let it come back out a few times so it could loosen up. It's the same kind of switch that controls the interior light on some refrigerators and car doors.
Easy fix! Happy camping!