For diagrams, have look here (no 600, but apart from engine, most
should be equal to a 500);
http://www.autolib.diakom.ru/CAR/Mercedes-Benz/1992/500SEL/SYSTEM%20WIRING%20DIA
GRAMS/

As for door panel, look here;
http://www.mercedesshop.com/Wikka/W140DoorCheck

This is for a facelifted W140, but the only difference
should be the placement of screws in the armrest.

Other good sites;
http://www.v12uberalles.com/
http://pages.prodigy.net/jforgione/MB_S500.html

br,
syljua