Latest development on my C215 door closing problem. Now the self closing feature is completely inoperative on the driver's door. If I shut the door manually (slam it), the window goes up immediately. So it seems my problem was in the self closing feature of the driver's door. The passenger's door is still functioning normally. I haven't had a chance to take the car to my mechanic, but this new development should make it easier to diagnose. Is this something for a DIY project? What part would I need? Is it a difficult repair? Should I take it to my mechanic? Thanks for your help M.B. Doc!