You did not indicate whether the central locking pump works or not. This is basically a vacuum system for the door and trunk locks. Pressing the lock/unlock button on a key fob will give you the answer before you go through the effort and expense of replacing it.

I admire you no end for this project. It is dirty and smelly, but no more than some fantastic barn finds that have turned into terrific antique vehicles. You are progressing methodically with a deep clean every step of the way, and I think you will be thrilled with the result when the journey is complete.

Curious what was the "clunk" that caused her to park it. 180k miles is high (I am only at 65k and 44k) but there are many reports of these SLK320 engines going over 300k miles.