Mercedes GLC Sound System Failure

That's frustrating! I had similar issues with my GLC. Try the auxiliary input. Even if you don't use it, it could show if the amplifier is the problem instead of the head unit. If all sources are silent, the amplifier or a common speaker connection are more likely.

Good idea about the auxiliary input! Where is the amplifier in the GLC, and how hard is it to get to?

I can't give you the exact location or repair steps, but check the service manual or a good workshop. I took mine to a local workshop. It turned out to be a bad bass speaker.

Thanks for the help. I went to the workshop, and the bass speaker was the problem. It cost 280€ to fix. Happy it's done.