I found a part that you might need
Got this from w w w . t r a d e motion.com
http://w w w .trademotion.com/partlocator/index.cfm?action=getJointLocator&siteid=214089&chapter=§ionids=25,0&groupid=10050&subgroupid=20061&componentid=60962&make=67&model=ML%20Class&year=2006&catalogid=1&displayCatalogid=0
take out the spaces on the www
Description Year MSRP Price Core Price Your Price
Lock, ml500, ml350, right
2006 $408.00 $318.24
Lock, ml500, ml350, left
2006 $340.00 $265.20
I am not sure if that is the one. You will have to double check with the site.