Although not a complete answer as I don't know the pin numbers ...
You can plug it into a NTG2 car (A/B/W203-C/CLK/ML/GL/R)
Do not plug it into a NTG1 car (E/CLS/SLK) without an adapter loom
If you look at this picture, brown is ground, red is +12 (the wires roughly in middle of the picture)
http://www.mercupgrades.com/db-artic...s/image016.jpg
Richard