When I bought my 190E the front door locks didn't work. The trunk lock was the only one that would lock and unlock the car. So I just used the trunk lock all the time.
But then, while parked at Assateague, I tried to unlock the car and I felt a snap (transferred through the key) and I was locked out (no locks working). Luckily, it was at the beach so I had the windows partially down. With a half an hour or so of effort, I was able to get into the car, but I can no longer lock it. I visually inspected the driver's door lock and the trunk lock. They both have obvious physical breaks in their workings.

So I'm looking at replacing the door locks and the trunk lock, but how does that work with the key? Do they all come with new keys? Are they keyed the same as the original somehow? Is there a key cylinder that I will switch to the new locks so keying doesn't change?

Also, where is a good place to get these, and about how much should I be expecting to pay?

Thanks.
-Brett

Why not just remove the handles, pop out the lock cylinders, and clean/lube. If there are any defective leaves in the tumbler you will see them and can remove them. If you remove 1 or 2 out of 12 to 14 leaves, the lock may be slightly less secure, but most importantly the same key will still work.

This is a pretty easy job, I did my driver's door lock a month ago when it seized. I did have to remove a couple leaves as they were bent either from not enough lube or from trying to force the lock to turn (by me). Now the lock works like new!

Cost was about $2.50 for graphite to lube after I soaked and cleaned all the parts with engine degreaser and a toothbrush.

Do a search - there's plenty of info here (including my resulting post).

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I wish that would take care of my problem. (I'm always for the quick, cheap and easy fix when possible).
My locks are not sticky at all. The action is great. The problem is that there are broken pieces (in the trunk lock it is plastic, in the door lock, metal) that link the turning elements to the mechanism that unlocks/locks the whole car. Perhaps I'll get some pictures of the problem pieces and post them.
-Brett

You should be able to buy the parts to repair the trunk lock at the dealer--relatively cheap as I remember. Locks are ordered via VIN number and should work with the original key.