I have a C300 2010 with the small screen and Audio 20 system and I just installed the RoadTop device. Everything works fine, but then I closed the doors and locked the car which is when it stopped working. I suspected the fuse and I was right. I bought some new ones and replaced the old one (I think number 26). I tried again and it worked fine. Turned the car on and off 3 times and still works. I got out to lock the car and enter again, and same thing. The initial time I changed the fuse, it was actually burned. The second time I couldn't see any visible damage to it but changing it got the RoadTop device running again, so I am not sure if it's the fuse or the fact that I pulled it out and put it back in.

Another thing to note, I didn't see an LVDS cable running to the monitor so I couldn't plug anything into the RoadTop device, but the system still worked fine. There is an LVDS cable running to the head unit though. Does anyone know what this could be? Thank you!

UPDATE: Seems like fuse is ok, it's something else. Radio works but I have to turn it on/off manually and the button presses are delayed (change radio station etc). Does anyone have any leads?