Left rear power window quit working from either door or console switch. Window won't go up or down and will slip down to about two inches below fully closed. You can pull up the window to fully closed, but it will slide down by itself again to about the same position. The door makes a funny sound when you close it... it is a tinty sound like the glass might break if you shut it hard. It doesn't sound like it closes solidly even though it lashes perfectly and locks just fine. Suggestions?