Recently installed an android head unit in a 2004 E320 with HK sound. Used fiber optic decoder box to route sound from HU to MOST network and therefore the trunk mounted amp and finally speakers. The fiber optic boxes on the market only have one pair of RCA type inputs, meaning you lose front to rear sound distinction. My question is: if I installed a second fiber optic box for the rear right/left channels and plugged it into the MOST ring at the port formerly used by the CD changer, would this restore full range of sound front to rear?

 

I don't think there's any point for just audio as that is always engineered for stereo output. i.e. 2 speakers. Only reason this could be useful is if you wanted to use your car as a home cinema and watch DVDs on the tiny screen in the dash. If you found a solution to this you could be enjoying the full surround sound experience within your car.

I'm interested to hear more about your installation because I'm just about to do this myself and my car is the same MOST setup, 2005 model. Did you follow any instructions, what cables did you connect, did you bother running anything to the boot?

 

There are a few well documented threads already on this forum that are very useful. My install still has a few loose ends as my son (this is his first car) was only home for a visit. The new headunit is an Atoto A6 PF based on YouTube reviews. We got the Xtrons brand fiber optic decoder box as it was a proven entity here on the forums and cheaper than some other brands - probably all the same under the plastic shell. Get a quality fascia panel as fitment on the cheaper ones is not as precise.

The only connectors on the rear of the OEM HU were the AUX plug and the connector containing the orange Fiber Optic wires and three power wires so in our case there wasn't much of a factory harness to match up to - your application my vary. To get basic function to the new HU you will need 3 wires: ground, battery (always on 12v), and ACC (only on when ignition switched). The switched power will be the one to hunt for behind the dash as the 3 connected to the OEM HU were ground, battery and a "less than 12v but still powered when car is off" flavor. This wire will leave your radio powered when you leave the car and probably result in a dead battery. We tapped the cigarette lighter wiring for this switched power and reused the original ground and battery wires of the factory HU plug. These 3 basic wires and the sound wires to the optic decoder box (box needs its own ground and Battery wires connected) get you basic lights and sounds. The remaining intimidating mess of wires is really just bells and whistles.

We removed the CD Changer and replaced its absence from the MOST loop with a fiber optic bypass adapter. In hindsight , we could have left it intact as the door to the "secret" cubby were the CD changer once resided does not function without the OEM HU. Restoring function of this door is one of the loose ends I am working on.

There was no radio antenna wire present behind the dash to plug to the rear of the new HU. That is the one wire I may need to run to the boot. I did see one antenna type wire among the wires under the center console but I suspect that is remnant of the defunct TeleAid system. The radio antenna wire wasn't of importance to my son as he was happy to connect his phone via wireless Carplay to the new HU and play his Spotify. Next time he is home the car may get a 5-6m, fakra connector, antenna wire run to the boot - just to staisfy my OCD and tie another loose end.

We did not install the CANbus decoder box to restore steering wheel controls YET. In my research, the cheap red tinted plastic boxes are just as capable as the expensive PAC, AXXESS, etc boxes for a Chinese android HU. The name brand SWC boxes appear to be tailored to work with the big name brand stereo manufacturers that aren't using open source Android operating systems. Someone please correct me if I am wrong. I did scavenge a CANbus connector from under the dash of a MB at the local salvage yard for the later connection of the decoder box - one small factory proper connection as atonement for the sinful splices I've inflicted thus far.

 

I've done the installation this evening.

It sounds like your car has the same connector to the back of the old headunit. 2-fibre and 3 copper wires.

I got everything working except... the sound. It looks like I bought the wrong model decoder box for my car type. There's more than one available and my model isn't listed for the decoder I bought.

I connected the CANBUS wires to the socket under the floor just in front of the left seat. Take out the mat, there is a line along the carpet in front of the seat. Lift the carpet up to the door tred plate and pull it out. Under the carpet is some plastic trunking and inside the circular section there is a connector called X30/5. Might be different on a E-class compared with the CL. But the essential point to note is you can connect the stereo to the closest CANBUS plug. It doesn't have to go to the boot so it could be a lot easier if you find one close to the stereo. It's a little rack of brown & brown/red wires (brown/red is CAN-H) and there are empty positions on the rack which you can add your stereo to. i.e. a bus.

 

Congratulations on getting most of the way there. The Atoto has a pair of line converters that change the wiring harness outputs to RCA plug outputs that in-turn go to the optical box.

The rack of brown wires is what I scavenged. When I do install the canbus decoder box I won't have to splice into any of the existing brown wires, I will have a dedicated (salvaged) plug to insert into the rack.

Sorry to read that the optic decoder box was wrong model and that is not something you can grab at the local shop. Hopefully Amazon can have one on your doorstep soon.

 

Can't find any on Amazon. Only eBay. So looks like I'll be without stereo for another week. Only thing that bothers me is that I might have something else wrong and changing the box will end up being a waste of time and money. I've written to Erisin to ask if there's any difference but I'm not expecting a clear answer quickly.

 

hi @dw00 are you able to restore the CD changer door function ?