not all the time, automatically, you know... it gets dark outside and viola! the headlights and the fog lights turn on. I mean, that makes sense to me, before I put euros on my car, id use the headlights, foglights, turninglights, heck even a couple flashlights to see where the road was...

Everyone else... wah wah wah just cause you don't have a new benz doesn't give all of you an excuse to be surly. The car doesn't have auto headlamps, the man wants autoheadlamps, he just paid $60000 for a car without autoheadlamps, let me tell all of you right now, if I paid that much for a car, id what autoheadlamps, oh yea, and auto air vents, and auto coffee maker, shoot, for that kinda cash they better throw in an automatic trash compactor!!!

Now back to the light, im assuming that the sensor trips a relay which turns on the light, bypassing the cars built in wiring. If this is true, the built in fused light sensor would detect power going to the bulb, but no power going anywhere else, which would cause it to think that the bulb is fused and thereby not conducting any current.

As far as aftermarket bulbs go, I don't know what the stock ones look like on a new E-class, but I really like my cool blue bulbs that I picked up for like $10. The light is obviosly no brighter, but the white (not blue... go figure) hue is definetaly more pleasing to the eye and it makes the car not look like an old piece of junk...