You don't have a digital camera you could take a pic of your engine compartment with do you ? I have a 1979 (non turbo) wagon I will go look at .... Greg

OK,, mine looks the same.. #1 glowplug is connected to the engine block at a bolt about 3 inches in front of it....

You almost certainly have a rectangular black box with the relay inside... keep looking on the "wheel house" (MB term)in the engine compartment..

surely somewhere in these archives are some helpful facts....

http://www.peachparts.com/shopforum/search.php?action=showresults&searchid=114130&sortby=lastpost&sortorder=descending

Greg