guys - the p switch does turn on your parking lights, and if you are in the U.S. it does nothing. From the factory MB does not "activate" the fog lights because they violate the us law of foglight distance from the ground to the light - its too high. Personally, I activated mine because they are very helpful at night. Here is how you can do it:
1) you'll have to pop the hood and find the rubber cap for the inner most rubber cover for the foglights on the headlight fixture. Pop these off and put a pair of bulbs in ( I used Silverstar Ultra's)
2) give your new bulbs some power. pop the fuse box open under the hood and wire fuses K29 and K30 together with a small wire.
3) I did this about 2 years ago and I love them. Whenever you push the P switch, your foglights will work which is now wired to your rear foglight as well (your driver side rear lamp is brighter than the passenger side, significantly brighter for foggy driving).
I am seeing a 15-20 foot difference on the side of the road at night. They don't illuminate the road further away but side to side is greatly increased. This helps me especially because I live in Central Pennsylvania and we have a larger deer population than cities. It has helped me avoid multiple deer this past winter.
Here is a link to Cal45fan's original post on it with pictures and instructions. Modify them to meet your own needs. I didn't even solder them, I used a short wire with little metal clips on the end and just clipped one end on each fuse and it has been working for 2 years. Thanks and I hope you guys get your foglights activated asap and enjoy the new lights! :thumbsup: