black lever in the door frame, it controls seat belts!
 

So I have heard this question a few times and have always wondered myself. What is that black lever in the door jam/frame? I was trying to fix my passenger side seat belt and came across what that lever controls. Some seat belt mechanism!! here's a pic. As for what it actually does I'm not sure, but definitely seat belts.

http://i361.photobucket.com/albums/o...r/100_0636.jpg http://i361.photobucket.com/albums/o...r/100_0637.jpg

It's a release that pulls the belt taught after you open the door. That way it doesn't get in the way when getting out of a vehicle.

ah, that makes perfect sense.