Just replaced mine with much help from the above pics and write-up. Thanks for posting! My philosophy of auto mechanics has always been "if its already broke anyway, take it apart and try to fix it-what's the worst that could happen?" Well, I'm here to tell that there don't appear to be any, as they say, "user-serviceable parts" inside, but I do have a pile of parts outside of the housing, anyway. There is a tiny metal tab that you can see if you pry off the small access panel halfway to the tab that sticks in the steering shaft. This is after the tab launches itself to the far corner of the garage under the force of the hidden spring underneath (surprise!). Anyway, this tab seems to be guilty of having worn down enough to not do its job. To remove this, you have to take out the rotating part of the cylinder that the lock seats into after removing the electrical switch from the back, then beat out the large peened-in cap at the opposite end of the steering shaft lock tab. This little tab is made of sheet metal and is also under spring tension and is released to ricochet around inside after you pull the assembly apart. Once I got to this point, having completely destroyed the assembly in the process, I called up Mercedes, who informed me the only way they could look it up was with a VIN from a Mercedes. I hoped it wouldn't come to this, but I sheepishly told them it was for a Crossfire. He then hit on the idea to go out and get a VIN from one of their cars and I got my part. I can say that even if my BFH hadn't damaged the thing, it would have taken some major mojo to get the thing put back together correctly.