I have a 2006 330i and I have noticed that when the car is off and the doors are locked, the start/stop button flashes on and off. The time between when the button lights up and turns off is about every 30 sec. When the button lights up I can here a motor or something turning on briefly possibly its activating the door locks. Has anyone run into this before and possibly know what could be causing this. Car starts ok but I am worried it will drain the battery.