The power door lock won't lock the rear driver's side door. Window goes up and down normally, but when you hit the key fob, or the inside switch, all doors lock but the rear driver's side. Also, when you open that door, the interior light doesn't come on. What's going on? Pull the door panel and just take a look?

 

My truck is having a similar problem, but it's the passenger rear door and the door won't unlock al the way.