jbeditor

My wife's 2001 S500 has recently had some body work on the passenger side door at our local dealer (Southern California). When it came back we noticed that the left and right front speakers no longer produced sound. There is a speaker under the dash grill that does work and the rear speakers also work fine. I used to fade the sound back to the rear speakers for our kids to listen to their favorite music and make it tolerable for my wife and I up front, so at first I didn't notice that the left and right front speakers weren't working until one day I was in the car alone and attempted to fade the music back toward the front speakers. To my surprise the audio was already in a "center" position with equal sound being distributed to the front and the back, but all I could hear was sound from the center dash speaker in the front. We took it back to the dealer and they claim that there was no reason why they would have disconnected the stereo and supposedly checked the connections to the radio and verified that everything was hooked up. Is there any advise someone can give me to verify this myself? Pulling the radio out myself seems a bit daunting as I'm hesitant to mess with the dash. I also have a 2001 CLK55 and have pulled the radio out before without incident using the small metal "clips" that you insert on either side and simply pull the radio out. Our S500 has a COMAND system too if that makes any difference.