Hi Gregory,
Welcome to the Heartland Owners Forum.
The welcome back light consists of a magnet on the bottom of the entry door and a reed switch under the door frame. When the door is opened, the reed switch provides a ground signal to the Welcome Back Control Module. From your description, it seems most likely to me that the module is malfunctioning. The module is probably located behind the rear wall of your pass through basement storage, on the door side. I've attach a picture that shows the module, along with a diagram that is likely how all the components go together.