The wiring on my 72 250C is a little different, since I have the electronic distributor, but the heavy wire coming from the white ballast resistor goes to the positive side of the coil. I'll find my wiring diagram and see if I can give you any further guidance.
Okay - I found the wiring diagram in my Haynes manual, so take it for what it's worth. There are three connections to the coil. One wire goes from the ballast resistor to the positive terminal of the coil. The high-tension spark plug lead obviously goes to the distributor, and the negative coil lead goes to the distributor, where it is switched to ground via the points, with the condenser connected in parallel to the points.
How about a link? Got teased by skinnerbox and tried to find a 114 manual EVERYWHEREhere in town.[:(]
The Haynes manual is the most common and a reasonable guide for the home mechanic but if you want a very good book on the 114 try and locate (via amazon,ebay etc )a copy of the "motorbooks " manual,printed in the UK in the early seventies.They are a genuine workshop book unlike the pathetic Chiltons books,which actually use pictures of chev engines combined with plagiarised bits from Mercedes workshop manuals. There is also this site,which is material written "back in the day". http://www.laffey.co.uk/mercedes/mercedes280.php
The U.S. the 250 had CD ignition. The diagrams in the manuals I have don't show the correct wiring.
The ballast resistor connects to the coil +, and the coil - is connected to ground. The points/condensor wire connects to the CD box under the battery tray.
Linear Mode
