Which Rear light is this?

I am replacing the rear tail light on my 2000 E39, to the updated design. For the life of me, I can not figure out how what light is this. It has a bulb and everything, but I can not get it to turn on for any known function. The manual does not label it. I call it #5. What light is this?

rear fog light

Originally Posted by Nervous

rear fog light

For Euro models? It is red on mine. Do they have red rear fog lights in Europe?

Of course, it is red (since it is *rear*). Yes, for Euro models.

Originally Posted by Nervous

Of course, it is red (since it is *rear*). Yes, for Euro models.

Ha, I believe I have seen *JDM* ones with clear rear fog lights

I found some info here. BMW Rear Fog Lights

I also found this guy who wired it to be an additional brake light.

Lots of us in the US modify it to be an extra brake light.

Found my next project.

Originally Posted by tmvE39/E53/Z32

Lots of us in the US modify it to be an extra brake light.

Does it have any implications with the brake light sensor by modifying it to be an extra brake light? Does the sensor still work? Does it still show when one out of the now 5 bulbs are blown?