A good friend of mine has a 2006 Benz C280 4matic... she is having issues with her rear fog lamp... Basically on the driver side the upper bulb which turns on with the brake pedal would stay lit... now it works normal but she called me again and it says her brake light and rear fog have issues on her dash... im almost positive that she has issues with her wiring but i was just wondering how the rear fog works on this car... because she no longer has the owners manual

 

on that car the rear fog is the left side bottom inner bulb. there are 2 bottom bulbs and the one on the inside is the fog and also a fog bulb. . But if a parking bulb goes out....which is one of the 2 bottom bulbs it will substitute annd use the upper bulb as the replacement and it will stay on as if it were a park bulb and the bottom bulbs will quit working. so one of those bulbs is bad. make sure the correct bulb gets installed or youll drive yourself nuts trying to find what the problem is. compare bulbs with the taillight on the good working side.

oh and the rear fog lights comes on when you turn on the headlights or just the parking lights and pull the light swith out...1st pull front fog, 2nd pull rear fog and front fogs.