I did the same thing, I ran it into the 6 pin to run the city lights, but I also made a "Y" out of that wire. One end running to the 6 pin plug, the other running to my turn signal marker light. You can buy a push type plug from AutoZone that will fit the post perfectly. That way I have the city lights AND the side marker light....don't have to worry about being seen from the side...or the law.
'86 420SE Euro
904 Midnight Blue, Gray Velour
Dad bought it new, now I own it.
"A Mercedes-Benz is like a fine wine, it only gets better with age."