Ok, update. So as I posted way earlier in the thread, I decided to throw out the OEM navigation system and proactively be forgiven for somewhat decreasing the "OEM-ness" of the car; the nav was basically garbage (and I feel guilty for making the previous owner get it properly configured for backup cam operation, as it wasn't trivial). But after the DVD wasn't even being read properly (might have been due to the quality of the disc I burned... was trying to keep the original disc intact), I got annoyed and decided to do something about it.
Enter Android. I think there are probaly like two or three companies in China that make the actual devices, and then there are hundreds of customizers that adapt them into faceplates for various cars, and then on top of them, thousands of resellers on Alibaba. What it results in is basically the same devices being rebranded and resold under a variety of names, one weirder than the next. On the upside, oddly, it results in a very consistent installation and use experience, since many of the interfaces are generally similar and all of a sudden, every car you get into has a similar interface, which is surprisingly helpful in creating a unified user experience. Of my three cars, two now have an almost identical interface, and the third has a slighly modified one that quickly reverts to standard Android after a few taps. Anyway, I digress.
The install was supposed to be pretty easy, since the unit came prewired into a harness. Oh, but things never are, are they? I don't know why I always end up with cars where the wiring makes absolutely no sense. For all the hate I spew on the RS6 that I had, that was probably the only car where an Android device literally plugged in and just worked, no funny business.
It looks like the R63's wiring harness is not only unique, but also undocumented. Probably because it was such a limited run model, Mercedes did not see fit to document the wiring diagram in WIS, so when you actually look at WIS, it's kind of wrong (if you can even make heads or tails of it). Also, no websites list the schematics for a pre-facelift R-Class - everyone has the updated wiring diagrams for the NTG 2.5 device (the one with the exposed DVD slot and a SD slot on top of it, featured in the facelift model). For some reason, similar generation GL and ML cars also had a different harness, as if it made any sense to customise the damn harness for every car that rolled off the assembly line.
In specific terms, what this meant in my specific case was three things:
1. Rearview camera would not work by using a FAKRA-RCA adapter
2. Power would not work as expected, and
3. FM radio would not work.
Anyway, I first started by taking apart the dash. For posterity, this is what I started with:
Comparing the old and the new:
Since I had to run the 4G antenna and the GPS wires (in retrospect, I could've reused the OEM GPS wire, so maybe could've avoided running some...), I had to take out the vents. While the passenger side vent was a pretty easy one to take out, the center one was a right BITCH to get out. Besides the fact that you have to be an octopus to get all the clips lifted (many DIYs just say rip it straight out... but that's a really dumb way, since it really isn't designed to be ripped out - it's designed to have the clips lifted, dammit!), they are inconveniently placed, and are VERY hard to reach. It's a much smarter idea to just remove the slats.
Don't forget to remove the wires once you do have it out.
............... except once you remove it and have it in your hands... you realise what a DUMB idea it was to remove those slats. The design is INSANELY hard to put back together - think of a structure with the rigidity of a house of cards right up to the moment where you click it all together, at which point it regains rigidity... but until then, you will swear, curse and invent new words because the goddamn slats will keep sliding, falling out, flapping around - and don't even get me started on the metal bracket behind them that, in principle, makes them all move up and down in unison. A guy in a Youtube video couldn't take it anymore and superglued them together so they hold together... I was laughing at his impatience until I spent two hours putting the f'n thing together. Fortunately, eventually, the wife stepped in and got it all reassembled in a quarter of an hour. I have no idea wtf she did. Anyway, it looked like this after her wizardry was complete - and no superglue used!
A note on the passenger side vent. Not sure if anyone is ever going to be looking for a DIY on how to remove the passenger AC vent for a W251 Mercedes Benz R-Class (R350, R500, R63) (see what I did there...) but there's a sneaky side snorkel that must be removed before the vent will come out, and of course, you can't see it until you take off the side panel. Smart design. Many hairs lost. Fortunately no clips broken because I knew there's secret trickery afoot, but took me a while to figure out where it was.
Next up, connect the Android unit. I like taking a pic of the whole console undone - in every car, it looks like a complete disaster because of all the crazy wiring, so it's fun to show this picture to people.
Ran the wires to the right side of the car. With the center vent out, it was a piece of cake, there's lots of space to put hands through. I didn't have to undo the A-pillar either - just ran the wires at the bottom of the trim, there's enough flex in it to bury them both with a trim tool. The gold colour box is a SIM card unit for when I decide to add a SIM card to it... for now, I just use my Wifi hotspot.
Main quadlock wiring harness with everything in it:
So I read somewhere that I can use the onboard backup camera without wiring another one. I really wanted this to be true, because I was absolutely NOT looking forward to undoing the rear hatch trim and running new wires (not to mention it would look STUPID to have both the OEM and an aftermarket camera). Tried blindly connecting the FAKRA to RCA adapter to various FAKRA wires, but after getting no signal I went to read the wiring diagram... and turns out that none of the FAKRA wires are actually the rear view camera (unlike on the facelift NTG 2.5, damn it). Further searching sugggested that the backup camera video feed is actually a wire on this quadlock connector, and the suggestion was to tap into it. I don'really, really don't like tapping into wires (with those tap-a-fuse devices or whatever they call them) because the whole concept freaks me out - essentially, you're slicing into the insulation to create contact with the wire; but what if you pick the wrong tap-a-fuse, and it cuts the wire clean off? Or creates a failure point because it becomes weaker in that spot? I really don't dig that, and I realised that there's a much simpler way to tap into this wire... like this:
Yup - since the rest of the connector is ground for the camera + some random unused wires (they don't even have a counterpart on the Android unit's harness), I could just remove this connector and tap right into it. It's not shown, but the other side of the white/black cable is just a standard RCA plug; I cut an old cable, cleared the shielding away, and just soldered the copper wire to this pin. Success!!! I got video signal, and it looks just fine. Low resolution, but it works.
I want to replace the OEM camera one day; I've seen OEM mount Chinese cameras, but they all come with an RCA wire; the OEM camera has a 4-pin harness. If I can ever find a defective camera so I can chop off the harness, I will replace the camera with a more modern / better field of view one. It should be great. Unfortunately, the OEM cameras are all $90+ on eBay ... certainly not paying that to just chop the harness up.
Another issue I ran into is that pin 16, "MOST wake up", was being treated as an ACC by the Android unit's harness. I thought the unit would switch off by itself, so I left it, and it did switch off... as did the rest of the car, including door locks and keyless entry. I had to discover how idiotic the Mercedes door unlocking design is: sure, there's an emergency key, but unlike in a normal car, where you insert the key, turn it to unlock, then pull the handle, with this car, you turn the key, hold it while it's turned (because it's spring-loaded and wants to return), then pull the handle to unlock. Guess how many kind words I had for Mercedes design engineers at 6am on a school run? Let's just say the Delica got some unplanned use that day. Later that day, I also discovered that apparently this car is too upscale to be boosted by pedestrian vehicles, as my Delica was unable to boost it, so I spend another hour on the internet searching how to boost an R63 - I thought I was maybe using the wrong boost points or something. The things you question yourself about. Finally, I ended up charging up my portable booster, and that worked great - the car started up just fine.
Finally, after extensive research, I pulled the pin from the harness to disconnect the MOST wakeup wire. And amazingly, everything started working as expected. I have no idea where the unit gets its wake signal now, since there's no ACC wire in the harness (none of the wires on the large quadlock have switched power. It's a mystery). The car hasn't died since, so I guess I got it right this time.
I finally reassembled everything and here's how it looks like!
Overall, very happy with it. The screen is huge, Waze works well for traffic (with a Wifi hotspot) and although you lose multichannel and the sound output is technically analog (you lose optical), sound quality is still perfectly fine.
The only thing that does not work is radio. In more wonderful design decisions, there is an onboard AM/FM signal amplifier. In newer versions, there's a pin on the harness to power it, so you feed it 12V, it turns on, and Bob's your uncle, you have signal. Unfortunately, in the 2007 R63, the wire isn't there, and it's powered by unicorns murmuring swear words in German, so I don't know how to get it to power on. The research continues. I don't really listen to FM; the wife does, but when she drives I'm generally not with her, so it's a problem that's somewhat lower on the list of priorities, lol. In seriousness, though, I'll have to figure it out, hopefully someone can read wire diagrams better than I can.