mrichmon0

I've completed the install of a new Android based headunit in my 2004 C320 Coupe. This car was ordered with the Premium Sound system so it has the Bose power amp connected to the stock Audio10 head unit via D2B fibre optics.

My goals with the head unit replacement were:

• Add CarPlay to the car
• Maintain steering wheel controls (at least for volume)
• Avoid running wires to each speaker -- i.e. use the existing power amp
• Minimal modifications to the stock wiring harness -- i.e. I want this head unit install to be reversible
• As near to stock look as practical

Overall, all of these goals have been achieved.

I used the XTRONS IA82M203LS head unit and the unbranded blue D2B fibre optics decoder box that is available on Amazon or AliExpress for the w203. The decoder I used was named "Car D2B Digital Data Optical Fiber Decoder Most Box Car Radio Adapter for Mercedes Benz ML CL SL E C S CLK Class" and listed 2001-2004 C/CLK on a label affixed to the top of the decoder. The D2B decoder is only needed for cars with the premium sound package. For cars with the standard sound system this head unit is plug and play. Cars later in the model year may have the MOST fibre optics which require a different decoder.

With these parts the only modification to the stock wiring harness was to tap into the cigarette lighter 12V+ to use as a ACC+.
The XTRONS head unit came with two ISO adapter harnesses for either the Audio10/Audio30 stock head unit, or the Command system. My Audio10 used ISO 10487-A (8-pin) and 10487-C (10-pin) connectors. To power the decoder I tapped into the XTRONS adapter harness for GND and VBatt+. For the ACC+ I ran a wire to tap into the cigarette lighter. The final wire for the decoder is the D2B wake up signal. This is available on the 10487-C (10-pin) connector that the XTRONS head unit uses for the CAN BUS integration. I de-pinned a wire from the Command ISO adapter harness and used this as a new pin on the 10487-C (10-pin) socket provided with the XTRONS. This completed all the necessary connections.

I relied on this thread for the Audio10 pinout details. https://mbworld.org/forums/audio-ele...rs-pinout.html
The D2B wake signal is on Connector-C4 in that thread.

For this install I am not planning to install a backup camera. I may install an external microphone, but based on a quick test the built-in mic is providing decent sound quality for calls.
Note that this head unit does not require ACC+ to be connected to the head unit. Instead, the head unit interprets a vehicle wake CAN BUS message when the key is inserted into the slot (before the key is turned).

I removed the stock CD changer and bypassed the CD changer fiber optics using a bypass loop. My CD changer has not worked for years and would not work with the new head unit. Additionally, the D2B fiber optics require all devices on the ring to be powered on for the fiber optics loop to function.

I only have the steering wheel volume controls working. Perhaps with some config changes the other steering wheel controls will work.

Thanks for the various threads I read on this forum to work out the details for this install.

C230 Sport Coup

So you got it working? Sweet! Yeah, my CD changer gave up the ghost years ago.
Took it out, sold it on ebay!
I have the Euro in dash single CD (Audio 10) and an in dash FM modulator that works so so.
Thanks for posting!

mrichmon0

I found that a few more steering wheel buttons are actively controlling the head unit. Page up and page down on the left side of the steering wheel are acting as forward/back. One of the telephone buttons takes the headunit to the Home Screen.
There may be configuration options to adjust this. Otherwise, a bit more time driving with it should reprogram my muscle memory.

I_am_Sam

Hey mate,
Wondering if you could answer a question for me.
I have a very similar setup as you, very similar looking unit and car. However I don't have the amp in the boot.

I have tried for years to get the Steering Wheel Controls (SWC) to work but to no success. (I have a can bus decoder that works, it wakes the unit, shows doors open etc.)

My question is, did you ever try to use the SWC without connecting the D2B adapter?
(eg: testing your setup with the head unit installed, but not the D2B adapter and trying to change the volume)

It's just that I have read from some posts that the SWC operate on the D2B network - and I'm thinking that perhaps the reason some people have success is that they have used a D2B adapter to get their amp to power, but at the same time that is keeping the D2B network alive and the SWC find their way to the Can bus network. So before I try the loop deleter for an adapter like yours, I thought I would ask.

Cheers!