Me 2.... Would like to add fog lights to my 2015 C350.

No one has done this?????

 

MB thinks you don't need no stinkin' fog lights!

"Low-beam headlamps
"Even if the light sensor does not detect that it is dark, the parking lamps and low-beam headlamps switch on when the ignition is switched on and the light switch is set to the [Manual] position. This is a particularly useful function in the event of rain and fog. [emphasis mine]" (P. 125, in the Operator's Manual.)

Just because you thought you needed fog lights all these decades past doesn't matter. However, I'm not sure MB is wrong; the fog lights on my 2007 C280 (W203) weren't bright enough to drive around in an unlit parking lot. The LED running lamps on my present U.S interactive LED headlights are brighter. You have to switch them on, though, using the Settings menu of the instrument cluster (not COMAND). (P. 247, in the Operator's Manual.) You should stop to do this. Then they are always on. They will keep other cars from running into you head on. There is a rear fog light for the same purpose. How the rear fog light improves on the regular tail lights, I wouldn't know.

I have not had to drive in thick fog in my present C300. I foresee two possible problems. One, the daytime running lamps are too high for proper fog lamps. If so, you would have to stop to turn them off (if you had them on). The other problem is that the low-beam headlights might have the same problem. However, the low-beams of my present interactive LED headlights have a very sharp upper cut-off. This should be ideal for fog. You can't turn the low-beams off (at least at night). If they are off in daylight, you can turn them on, by selecting the manual headlight control position (the position to the right of Auto) on the light switch. If all else fails, you have to wait until another vehicle comes by and follow him. Just be sure to leave enough following distance, so that if he goes over a cliff, you don't go with him!

 

I too like the "look" of fog lights, but also the added illumination they provide on exceptionally foggy nights! The standard black plastic blanks look cheap and out of place! Any suggestions on how,what,where and how much to retrofit these?