I would not rule out a problem that may be in the electrical part of the ignition switch. This part screws into the rear of the lock cylinder and has contacts for everything requiring power with the key. If a connection has broken within the switch because of wear and tear then replacement is necessary.
Attached pic is for illustration only

Attached Thumbnails

 

__________________


Selling used Mercedes parts on Ebay...always changing...
cdplayer51 take a look!
____________