my fridge in my 310qb travel trailer does the same thing. It is the fan. When it cuts on you can hear it inside the trailer. I had it checked out just to be sure, but they said it was fine and working properly. If your trailer has the 2 louvered covers for the fridge on the side of the trailer then it is probably your fan. The trailers that just have the one cover have a vent on top of the trailer for the hot air to escape, but the ones like mine have the fridge in the slide out so there is no vent on top of the trailer for the heat to escape, and there has to be the the 2 louvered covers with a fan in the top one to help pull out the hot air.