So I just got my W126 last night.

I know Im supposed to post a car picture first. It was dark and then I started taking tings apart.

I could not wait to dig into the battery box area behind the bulkhead. I had to see if the CA car had any hidden rust.

Thankfully it was rust free down there (other than the tray itself)

But while I was in there I found this odd sensor. (the one in my hand)

IMG_0068 by ttownthomas, on Flickr

It says muRata on it. It looked like it was hot glued on to something at some point and there is no MB part number. <-makes me think it is not a factory part

I found this site: https://www.murata.com/en-us and the logo matches.

Could it be part of an aftermarket alarm? My best guess is some sort of buzzer