My 1986 300SDL, and a 1986 420SEL seem to use the same part. I'm sure other models do too.

http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1KT19E3PR1KT19HDV7&year=1986&make=MB&model=420-SEL-001&category=R&part=Sampler+Blower+Motor

This might be what you're looking for.

Best Regards,
Jim