W124 door trim
 

I've noticed on the W124s that there is a small clear and square plastic piece of trim in the very middle of the interior door. What is the purpose of this? Is it a light? I know there is a puddle lamp on the bottom of the door, but is this supposed to be part of that system?

I have a few 124s, and am not familiar with this piece. Do you have a photo or a description of location?

I may have been mistaken, I believe it is only on coupes. Any coupe owners wanting to take a guess?

It's for the service manual booklet thing to show when you're due for service next.

Interesting feature but it seems like an odd place to put something to remind the owner when to service their car. I would have thought that they could have placed it in a more inconspicuous place such as behind the fuel filler door or on the back panel of the sun visor.