I didn't notice it was a manual, that makes it easier.

This is what I was referring to:

http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1CQ0J3JZ41W600J6FV&year=1982&make=MB&model=240-D-002&category=All&part=Ignition+Switch&appChassis=_any

It the part that plugs onto the back of the ignition switch and controls the electrical stuff.