Originally Posted by former NXMX5
It doesn't affect the stop lamp function. On rear fog lamp cars, one reverse lamp becomes the rear fog lamp (so you will only have one reverse lamp)
Actually it is the brake light that is illuminated (on US cars), not the reverse light. My girlfriend's C230 does just that. Thinking about it, if it were me coming up on a car and I saw a single white light I would think it was a motorcycle coming at me head on!