We bought our fifth wheel three years ago. We were advised by the salesman that every three years we need to replace the caulk seal around the air conditioner and vents due to the possibility of crac...
I would take it back to that salesman and ask him to show you the caulking that seals the air conditioner, since there is none. You can inspect and repair your roof yourself easily. There are tons of utube videos that show you how. Dave