Ginger, I hope you are reading this. It appears that your wiley ways are quite effective in gaining results! I congratulate you. In any of your discussions about your key/lock type problem did anyone mention the security system. I have a problem similar to what you had but unlike you no one responded I was thinking that maybe you could help me I am reposting my problem again hoping that you may be able to help. how bout it? later we could discuss posting photos!

1994 C280
I used search and read the posts - didn't see this wrinkle.
up north here its colder than a witches t t. There is so much salt on the road I don't know whether to drive or break out the tequila and lime. So there I was, couldn't take it any more and had to run Bonnie thru the automated carwash. meanwhile back at the ranch......the selection of music warranted a CD change, in the trunk I go. Well,,,,,the trunk lock had received a dose of water and turned reluctant. I gave the button a good poke and she broke loose and went in, allowing me to open the trunk. The lock mechanism stayed inset in the cavity like a frightened turtle. So a few gentle "closures" of the trunk lid made it pop out to its normal position. With the key in the trunk lock everything appeared to work fine. I can still lock and unlock the doors from the trunk lock. All is good........So I thought. I made it home. The next morning the ignition key slips just fine into the tumbler (neverhad any problems before!) but, and there's always a BUT, the key will not rotate the cylinder. I do not believe it is hanging on the steering lock because I can feel the lock ease when I turn the wheel. SO here is the question. How does the security system inhibit the ignition when the car is locked from the trunk. does it lock the tumblers in the ignition switch somehow? could it be possible that my trunk lock is influencing my ignition switch thru the security system. Or am I just another lucky MB owner?

so there it is, my story....it is slightly different than the original post. I now learn Bonnie lied, she was born in 94, not 96.
BTW, I really need this car to get to work, no work, no car

thanks