have the same problem with my 1994 MB. I had to replace my alternator and they still came on... I replaced the battery and they still come on. new belts still come on. at first it burned the main relay on the battery. I took it to an automotive electrician and they said they couldn't figure it out. Have you installed anything new and electrical? mine started after I put fog lights on my car. those two lights are only on when the alternator isn't charging properly so it sounds as though your alternator is going out, which is $100-$300 to replace don't go through a mechanic if all possible because they will charge you immensely to install it. its typically 2 or 3 bolts and shimmy it to loosen the belt off.HELP! C-class Mercedes alternator/battery light wont go away!!?
i have an 05 c320.. i would take it to an auto electrician if i were you. this seems abnormal
