I've got a '92 300SD, W140. The trunk lock has never worked as the key slot is corroded. As I generally use the remote Infrared to lock the car, this is not a problem and I have never wanted to unlock it with the key. However, the locking cylinder is coming apart and I would like to replace the locking mechanism. I don't care if the key works or not, but I do want to be able to unlock the car with the trunk IR sensor.

The question is, "is the IR ID embedded in each of the (trunk and door) sensors, or is it controlled somewhere centrally?" Put another way, does the IR sensor need to be rekeyed as the physical key does? I'm perfectly happy to put in a locking unit for which the physical key does not work, but I do want the IR to work, so I propose picking up a used unit if I don't need to worry about the IR.