E420 turn signal switch. 1997 model.
 

Any advice on changing this switch?

• remove negative battery cable
• carefully remove airbag (torx screws in hole on either side)
• remove steering wheel; undo electrical connections
• replace switch
• remove panel under steering wheel in footwell to gain access to connection
• repeat in reverse :cool:

Do a search for "combination switch" and you'll learn more than you ever wanted to know about the procedure.

G'luck and welcome

Maybe this will help, there are other articles under the DYI in the "resources" bar at the top of the screen
http://www.peachparts.com/Wikka/W210LooseTurnSignal

Job successfully completed, thanks for the info., especially that this is really called a combination switch. A friend has the T30 bit and an impact wrench, which easily defeated the 10 mm nut! :) However, this was a fiddly job, one to tackle methodically. Useful to have the front wheels off the ground to rotate the steering wheel to access the Torx screws.