have a 2006 DTS and noticed a couple of months ago the radio would not cut off when i opened the drivers door, last week the interior lights would stay on while driving and could hear the door locks actuate, the interior lights will come on whenever they feel like it, draining the battery. Pulled fuse for interior lights and they stay on, put fuse back in and they go off. Any clues on what is going on. Any help is appreciated.