Check the the Euro threads
...for answer to your questions. In my case (1991 420SEL) the city lights are wired as follows:
Run a wire from the #3 position in the 6 pin connector to the #4 pin (grey wire in my car) in the side marker connector.
To run the wire from #3 to #4 you need to buy a pin frrom the Benz dealer, I am not sure what the part number is, but if you do a search under member "Barrie" he lists the part number for the pin. It is a simple operation, just make sure that you solder the connections.
1989 300TE "Alice"
1990 300CE "Sam Spade"
1991 300CE "Beowulf" RIP (06.1991 - 10.10.2007)
1998 E320 "Orson"
2002 C320 Wagon "Molly Fox"
Res non semper sunt quae esse videntur
Not in this weather!