i believe i have the same problem but with the passenger side door. i really have no need of changing it since im the only one that uses the car but i've been looking on how to replace this part.
i found this at realoem.com: 51218199923
and
http://www.pelicanparts.com/cgi-bin/...51218199923-M9 if anyone can direct me to a guide where i can install this part myself rather than going to the dealer i'd appreciate it very much!