I thought mine were when we pulled out of the driveway Labour Day weekend. Upon arrival at our destination I went to light
and noticed the hatch door missing. My mind flashed back to when I was connecting the trailer and doing my checks. Yes I was interrupted a number of times and probably forgot to check the fridge
Believe it or not, I retraced our route onto the highway a couple of times after our return when I finally thought I caught a glimpse of what might be my vent. A week later it took someone else driving on another trip for me to be able to see it for sure. It was on one of those awkward spots on the shoulder that was difficult to remember the exact location to pull over, there was not much room to pull over safely. Each circuit on and off the highway was a 20 min trip. Two trips later and it was too dark to see. 4 days later, I found the time during the day to try again. Believe it or not, this time I was successful. The vent was there, but not in the best of condition.
I think it can be fixed, but I'd need an original to get the right contours for the louvers. Is there anybody in the Greater Toronto Area that has one of these Dometic VT-24-1 lower vents? I can make a "rubber" mould of the 2 countours in need, in less than 10 minutes with no effect on yours.