I found this site while digging for answers on my car. I thought that others may find it of use. It is a Russian site (I think) but the drop down menus are also in English to help.
It covers a lot of car models

http://autolib.diakom.ru/CAR/Mercede...NG%20DIAGRAMS/

The link is the one I copied with I was pulling stuff up on my C280. It has other cars if you change the drop downs