Japanese head unit wiring

Hey guys,

Its my first post here...I recently purchased a 07 Jetta FSi Turbo, a second hand import from Japan (we have a lot of those here in New Zealand)

I'm planning to replace the stock radio with a custom nexus 7 installation, similar to what you see here http://rootzwiki.com/topic/44698-04-jeep-tj-install/#entry1243194 or here: http://rootzwiki.com/topic/110146-car-install-nexus-7-2013-in-audi-tt-mkii/. I'm pretty confident with installing the tablet, but my problem at the moment is the wiring of the stock head unit.

The unit is a Clarion RNS-JP4, I'm pretty sure these are installed at the dealership in Japan, but I can find next to no info online about them. I'm hoping someone out there can tell me some more about the wiring setup, as it appears to be a little different from the stock units I've seen in forums and videos.

All I really need is the speaker wires, 12v constant and 12v accessory, I can probably tap into the fuse box to get my power wires too, so the bare minimum I need are just the speakers, but it'd be nice to know what each cable is! Is there an easy way I can test the cables to see what they are??

Here are some photos:

Photos

Photos didn't upload, here they are.

No idea, but you should be able to figure it out with a multimeter and a 1.5 volt battery. The wires in the harness with the blue plug *look* like standard wire colors. I'd bet that the larger gauge yellow and black wires at one end are constant 12v and ground. There may not be an accessory 12v, all of the North American MkVs that I've seen have CAN bus turn on. Try the smaller yellow or the red wire though. Worst case, run a wire from the fuse box or ignition harness. Speakers should be easy as long as there is no factory amp. Each pair of speaker wires will show resistance of probably 4 ohms (though some cars are 8, or rarely 2.) After identifying each pair that go together, use a 1.5v battery to pop the speaker to identify which pair of wires goes to which speaker. Again, based off of common wiring conventions, I'd start testing with the assumption that the white pair are front left, grey are FR, green are RL, and violet are RR. Solid color wires positive, corresponding color with a black stripe negative. If you see resistance that is waaaay off, like in the k ohm or m ohm range, DO NOT pop test them with a battery, they may be CAN bus wires. If no pairs show resistance in the 2-8 ohm range, start looking for a factory amp and you can get the speaker outputs from there. Beware, VW/Audi like to use half-amped systems a lot of times, in which one pair of speakers are powered by the head unit and the other pair runs off an amp.

Speaking of, I assume you are going to connect the line out from the Nexus to an amp to drive the speakers? Are you placing the new amp in the radio cavity or mounting it elsewhere in the vehicle? If it's going to be in the back, a cleaner solution with less wiring would be to grab the speaker wires at the kick panels in the front and along the sills for the rears, or even in the trunk if you can access them there.