There is a bulb behind each of those silver pieces of tape. I believe they are 194 style bulbs. A small piece of rubber hose can be used to slip over the bulb to help remove it from the socket. To replace the vent lights you will need to remove them to gain access to the bulb. Here is a writeup on how to get to them out. The information is about halfway down the page on the link below.
http://w124-zone.com/downloads/MB%20CD/W124/Index/MiscRef.htm#anchor4082673