My C55's head unit is no longer functioning correctly. Powers on but only shows the Mercedes logo and nothing else. I'd like to upgrade to something that has apple car play but crux is vague on whether or not I need to run speaker wire or if it'll use the factory amplifier. For those of you who have done this what was your experience and I'd love tips and tricks.

Do you have the BOSE sound system?

Check the rear right side of your boot - if you have an amp behind the carpet then you won't be able to use the stock amp without adapters that kill the sound quality.

Best to replace the amp/run new wires in this case.

If you don't have an amp/no BOSE then you can just plug and play a new aftermarket head unit.

I have the Harmon Kardon system. I assume that includes an Amp? I can check later after the F1 race. Thanks for the reply

No worries!

I didn't realise it was a Harmon Kardon system...

I know that Bose in C32s used optic fibre which is why you had to rewire however, not sure if that's the same case with Harmon Kardon so perhaps someone who knows can chime in

I know little to nothing about audio systems. I'd much rather change a water pump

Although I did retrofit Navi in my old SLK55 that didn't originally come with it. I'll look at the amp and see if it has those bright orange fiber cables.

HK system uses a fibre optic wire from the head unit to the amp, there are three ways to skin this particular cat.
Run a normal headunit of your choice and a MOST adaptor that plugs into the fibre loop and keeps the factory amp.
Run a normal headunit of your choice and run cables from that to the speakers, replace the speakers while you are at it.
Run a normal head unit of your choice and run some RCA cable to the amp location in the boot, replace the amp, you can replace speakers if you want to.

I think i'll start with the headunit, and a MOST adaptor. Do you happen to know of or have the link to purchasing a most adaptor?

Do you actually suggest replacing the amp and speakers at some point?

I just bought the car and have general maintenance items I need to accomplish before diving too deep into sound.

Update for anyone who finds this thread in the future. Looks like this is what I need.

Update update, fixed the command unit.... sort of. Removing the in dash dvd/nav unit from the command console fixed my issue.

How did you fit the hk connector to the most unit? I removed the orange cap but was unable to make it fit inside the most housing.

I don't understand, was your DVD unit in the trunk or part of the headunit?

I had this issue. The nav units die and cause the radio not to start up. The radio is probably fine.

If it's the drive, it won't read the disc and/or the door (screen) won't close. If it won't boot up and stops on the Mercedes logo, it's the board in the nav unit. You can swap a complete nav unit in from another car (doesn't have to be W203). Easy fix other than taking the dash apart. The nav unit slides out the back of the radio after removing a few screws. It's the whole top section (they're modular). A word of caution - watch out for used W251 (R class) COMAND units - many don't have navigation - just an empty box. You can also just remove the nav unit and restore the radio to normal operation.

Your original COMAND head unit is made by Alpine. Replacing with a Chinese made Android unit will add a great deal of functionality but will probably not sound anywhere near as good - especially through adapters. I could hear a HUGE difference when my COMAND failed and I temporarily put in the original Audio 30. Kinda flat and lifeless in comparison.

For the more advanced (or determined) among us - I swapped all the internals with a 2008 x164 (GL class) and added a "factory" reverse camera while retaining great Alpine sound and even ended up with a cool compass screen that shows steering angle... The only caveat is that you can't set the time zone, so the GPS hour will be off. You only ever see the clock if you use the navigation though. Also - my car isn't coded for navigation, so my center display time is set manually. I also added a fiber optic Bluetooth module that replaces the CD changer so now I have hands free telephone and streaming music. It even displays the song title on the head unit and allows me to skip using steering wheel and radio controls. My car wasn't equipped with the changer, so I had to add it to the fiber loop. It was a PITA, but I got it eventually.

Maybe I'll put together a DIY on both or either if people want it.