Here is the Russian parts site in English
Item #054 is the Glow Plug Relay
http://www.detali.ru/cat/oem_mb2.asp?TP=1&F=124191&M=606%2E910&GA=722%2E435&GM=717%2E433&CT=F&cat=44R&SID=54&SGR=330&SGN=09
This is the start of the site, they have 124.191.
http://www.detali.ru/cat/oem_mb0.asp?TP=1
Click on the 124.191 E300
Click on #54 Electrical Equipment and Instruments
Click on #330 Pre-Glow System