Mercedes malfunction notification

[KatDeLuna]

I've been having a malfunction warning come on my 2002 Mercedes c230 saying that the drivers side fog light needs replacing. So I replaced the fog light myself but the warning still came on even though the fog light worked. Went to Mercedes to have them replace the fog light thinking I used the wrong wattage light or what not. Mercedes got me a new light which worked but the warning still comes on. They said that the electrical may have been tampered with and they can try to fix it for $156 an hour for an indefinate amount of hours. So to save myself an unknown amount of money I thought I'd check with you experts here. Somebody suggested I fiddle with the electrical in case some wire is loose that is causing the problem, but I don't know if me "fiddling" is the best way to go....

Anyone know what this is all about?

[Phenix]

have you tried scanning it with a obd2 reader yet? that might show a few things. or there might be some sort of reset switch for the sensor. might want to check with a mercedes forum to get this one figured out.

[KatDeLuna]

I haven't done anything other than take it to Mercedes and it seemed like they had no clue what it could be.