My 1994 E500 headlight switch started getting finicky, sometimes stuck, and telling me it needs to be replaced. There is a fantastic HOW-TO at Pelican Parts:
LINK HERE: https://www.pelicanparts.com/techart...ght_Switch.htm
A couple of notes (some un-needed steps):- I did NOT need to remove my lower kick panel
- I did NOT need to disconnect the parking brake release cable from the handle
Headlight switch part number: 000-545-62-04 (it was $62 at mboemparts.com as of spring 2018)
Tools: 8mm socket, phillips head screw driver, 24mm socket or needle nose pliers, plastic interior trim removal pry bar.
This is a straight forward job, just take your time. My switch lasted 168k miles and I think I will never be replacing this switch again.
In case Pelican Parts link does not work at some time in the future I have attached a PDF of the instructions and photos.