Dometic fridge alarm and lights

Our RM8551 fridge keeps turning the door display on and sounding the alarm whilst the caravan is stored ie battery switched off and no mains. We turn the fridge off on the door switch and all is well then days later you hear the open door alarm and the fridge display and interior light is on so has to be turned off. There is no battery compartment in the door display as I was thinking low battery. So thefridge must have a 12v live separate from the caravan battery switch. An6 ideas.