The fault was shorting the 2 monovalve wires together. Easy to do after taking the connector housing apart to squeeze the contacts to make them tighter forgetting the key is on.
Do you have a more legible copy of this diag.? Where did you find it?
http://i323.photobucket.com/albums/nn447/Jeremy5848/Mercedes%20Stuff/Schematic.jpg
I think the same thing happened on my 83 300D a few years ago. I posted about it but didn't document or take pics of the fix and had to figure it out all over again.