This is the part you need:

http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1CQ0J3JZ41M30PRTHL&year=1983&make=MB&model=240-D-002&category=All&part=Instrument+Cluster&appChassis=-306958

As you can see, they are expensive new. I got a good on for about $75 from a salvage yard.