I am parting out a 1985 300D CA version. I have worked on various years of W123s and parted a few, but this one has had some unexpected finds.
1. There is another horn under the battery tray.
2. When I removed the instrument cluster I see there is a switch that appears to be checking the presence of the instrument cluster.
3. When I removed the vacuum truck lock actuator I see there is and additional device to prevent the truck latch button from being depressed.
And I can not figure out how it was installed.

Can anyone shed any light on these items? Never seen them before. What other surprises might I find?

that all sounds like alarm goodies.