1999 Plymouth Voyager

For 2 weeks now when I drive my van and step on the brake all my interior lights start flashing and the door light comes on as if one of doors were open it has gotten alot worse now all the interior lights come on and off all the time when im driving the door ajar light on my control panel is the only light that comes on and off I keep pulling over to check and make sure all the doors are closed tight and it still does it I also have electronic locks that keep locking when im driving. Do you know what this could be caused from? Its really weird driving down the road and the locks start locking all the time and the all the interior lights flash it is all the time