Ignition switch internals....
 

I've been experiencing the dreaded ignitions key insert / withdrawal difficulties that many of you have had, so I ordered a new electrical switch (part #4A0905849B/1) which is the recommended part number.
The new switch arrived and I can see from the general arrangement that it contain only the electrical connections and nothing mechanical - as in tumblers or locks.
So my question is, what exactly is causing my ignition key to bind in the lock mechanism - it certainly feel mechanical - and if I'm only replacing the electrical portion, hows this going to help insert / remove the key?
Has anyone got a diagram of the electro / mechanical components or can describe how it all works??

My ignition key turned with difficulty, got stuck, etc. I replaced the electrical portion of the switch, and all was resolved. The electrical portion can create a lot of issues!