Right Part? 190E, 1986, Ignition switch.
 

My friend has a 190E and the ignition key won't turn. I have read the "big lock post" and recommend he replace the ignition switch. Is thuis the right part? Are any other parts required?FastLane M5050-32967.
Thanks

I'm not sure, but I was under the impression that this problem is usually related to troubles in the 'Ignition Lock Cylinder'. The 'ignition switch' is just the electrical bit on the back.

I believe you can remove the ignition switch by removing 3 screws at the back of the whole mechanism, then try to turn the key. That would rule out the switch itself.

Best of luck.