A number of LD'ers who have installed LED taillights have also chosen to add a third center brake light, usually mounted on the outside of the spare tire cover. It's fairly easy intallation, for one can easily drill mounting holes in the fiberglass cover and one can tap into the wiring right inside the cover. There are a number of lights available, ranging from the simple to the snazzy, but installation procedures are the same for all.
Essentially what you need is the light and a resistor and logic circuit. The resistor came with the logic controller and was needed so the third brake light would not light when the turn signals were turned on.
You can find the materials for this project at:
http://www.commandelectronics.com/third-brake-lights.htmlThe resistor goes between the hot and ground going to the light. The installation guide said to install close to the light.
last item on the page is the logic controller with resistor included. It comes with simple instructions and fast shipping.
The logic circuit is just a yellow and green wire in and a blue wire out.
Here are pictures of Rod's installation on a '97 MB:
Contributors: Rod Michaelson