Hi Guys, I met the same problem as some of you recently after a huge rainstorm, everything works fine (CD or Bluetooth can play songs as usual) but no sound coming out from the speakers. I checked the amp and fuse box, no wet and nothing suspicious. And I went back and reset the COMMAND, still no sound. I tried to switch different sources, and found out sat radio shows "device unavailable" and media interface option is also "unavailable".

I disconnected the optic wires on the amplifier while the system is "playing music", and there is red light blinking at first and after a couple seconds it's gone, is that normal? Should the optic cables always have lights or always blinks? I am deciding to troubleshoot the media interface and satellite radio module, does anyone know the location of these two in w204?

I was going to disconnect my negative node of the battery because someone fix this issue by doing this.

I will also upload some pics later. Please help!

Btw I have a 2012 C300 4matic sport edition.

 

so my mechanic found the error code about 'MOST system loop broken' or something, ans attached is some pics shows on the screen. everything else works fine.

 

Definitely sounds like there is an issue with the fiber optic loop. Might have to go through everything connected to the system to see where there might be an issue. I don't know a lot about it, but I believe if one part of the loop has an issue the whole thing won't work. Based on your earlier post it sounds like the satellite radio module might be the place to start.

 

Thank you for the reply alfadude , i really dont want to go to the dealer, so i decide to try my best. Do yoi have any idea where is the sat radio module?

 

Sorry, I don't. Maybe do a search on here.

 

After 6 months with no sound, me and my friend finally fixed the issue!

5 months ago when my mechanic fixed the water issue (wiring, etc.) he told me the optic loop had some problems and it could be fixing it self after a couple days.

1 week later I gave up on waiting it to fix itself and started to do my research.

i bought 2 optic by pass loop online since both my media interface and sat radio is showing the error so I guess both of them need to be bypassed.

we located both devices, one in the back trunk and one behind the passenger side dashboard, by passed both, the loops should be good, but still no sound. FRUSTRATED.

Then it’s the long winter in northeast region and no one wants to fix cars during these dark cold days. However, the sounds came back for a couple seconds and then it’s gone, this happened like 3 times, and every time I am so excited cause I knew there is hope.

last month I finally graduated from college, and had some spare money to look into this issue, (thanks to trump) I send the car to the dealership and spent 160 dollars for a single diagnosis, I got a gle350 as a loner for 2 days and the car looks great but I missed my 6 cylinder power. They find the problem and it is the media interface issue, they told me they bypassed it and the sound came back. Quoted me 1200 dollars for a replacement hell no im not spend that much on something I never use.

I came back with the result and me and my friend took off the glovebox and bypassed the media interface. This time we only bypassed the interface not sat radio. SOUNDS CAME BACK, I ALMOST CRIED. By then I have been driving my car with no sound for half year and I almost gave up on it.

Now I love my 8 year third handed 100k miles c300 much more, and decided to drive it as long as possible. I hope we still got many years together.

hope my experiences helped with anyone trying to give up on their loved car, and as my friend said: if u treat ur car better, it will treat u better in return.

 

I'm having the same issue since like January no sound on my car and its also some most loop thing and I'm also in the north east lol but you said you bought that Media bypass thing what is it and where did you install it and how

 

here's the link you can find cheaper ones on eBay, but be careful don't get the wrong one.

I only bypassed the phone/media interface module which located behind passenger side dashboard and I removed the glove box in order to by pass it.
However in your case it might be different, it might be other module you need to by pass, so you may need to find them and by pass them one by one with the optic bypass loop. There are satellite radio and amplifier in the back trunk, and radio module in the central dashboard which is hard to access.
this video is helpful,
There could be other things caused this, check fuses and amplifier first.

 

Dead link any help?
I bought a female and a male most optic fiber cable but they don't fit I guess they had to be pre trimmed like yours