I've tracked down why my drivers seat headrest isn't working.. The motor is out, I tested it with 12v and no sign of life whatsoever..

But my question is, how am I supposed to take that out to replace it? Would this be a job for the Mercedes-Benz dealership??

Did you apply the 12v directly to the motor?
If not you should open up the seat and have a look.
Usualy the wiring breaks inside the seat.

__________________
-Marty

1986 300E 220,000 miles+ transmission impossible
(Now waiting under a bridge in order to become one)

Reading your M103 duty cycle:
http://www.peachparts.com/shopforum/831799-post13.html
http://www.peachparts.com/shopforum/831807-post14.html