I have an 2005 Deville and I'm having an electrical issue! The issue is the inside light stays on, does not fade off as normal draining the battery dead. Also the headlights just turn off they do not fade off as normal. When you click the key fob it usually would illuminate the headlights and inside light when unlocking. On the flip side when locking it would beep the horn, and doesn't do that any more either. Is there a fuse or sensor that has gone bad? Has anybody else had this problem if I've explained it right? Any feed back would me much appreciated.

Thanks,
Mason