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Has anyone tried this so far? I think i'm gonna do it pretty soon since i'm adding a computer to my car (props to Greekgod for many cool ideas) I don't wanna use an FM Modulator either... also i don't have a stock nav i bought a farenheit monitor and the housing..
 

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dskang100 said:
Has anyone tried this so far? I think i'm gonna do it pretty soon since i'm adding a computer to my car (props to Greekgod for many cool ideas) I don't wanna use an FM Modulator either... also i don't have a stock nav i bought a farenheit monitor and the housing..
I tried doing it and it works for all practical purposes, but I also did some experimenting on my own while I was doing it. SophieSleeps, maybe you can offer some insight to what I found:

According to your AUX input instructions. here is what you said
-------------------------------------
You are cutting wires:
(these are for the grounds)
Red pin 19
Yellow pin 15
Brown or Black pin 18

(these are for the signal +)
white pin 9
green pin 8
-------------------------------------

My own experimenting also came up with similar results:

Red and White are for the LEFT channel
Green and Black are for the RIGHT channel

However, I did not touch the Yellow wire at all, I'm guessing that is just an extra ground?

So anyway, as opposed to your instructions, I only cut 4 wires, Red, White, Green, and Black. Following this, if I ONLY connect back the Red OR White wire, I get SOME sound out of the LEFT channel. However if I connect the Red AND White wires, I get MORE sound out of the LEFT channel. The same happens with the Green and Black wires with the RIGHT channel.

This has left me to assume that even though the Red and White are supposed to a pair and the Green abd Black are supposed to be a pair, each pair doesn't seem to consist of one (+) and one (-). Seems like some sort of differential signal going through each pair of wires (all you electrical engineers out there, correct me if I don't sound right).

This also explains why when a normal (+) (-) source like my MP3 player is connected in, the sound level is low, like when I only connected one of the pairs of wires for each channel.

Does everyone follow me? SophieSleeps, I ain't trying to knock your instructions because like I said, for all practical purposes it works just fine, however I'm trying to fill in some of the blanks I found while doing this modification to my IS300.

If anyone else has tried this and found something similar and can expand on what I found, please post your findings!
 

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Podiatrist
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You are right...mostly.

The red and white are a pair. The white is the + and the red is the -.
As for the green and black you are also correct.
However, the yellow is a signal ground for them all, which is why my instructions included it.

Here is a factory diagram of that wire stalk.

 

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SophieSleeps said:
You are right...mostly.

The red and white are a pair. The white is the + and the red is the -.
As for the green and black you are also correct.
However, the yellow is a signal ground for them all, which is why my instructions included it.
Bear with me for asking a few more questions, but usually, the negative terminal (Red and Black in this case) are just grounds right? I mean that is why you connected those 2 to the Yellow wire. If they are ground, then that means they are at 0 volts. But, when I cut the, Red, Black, Green, and White wires (again note, I left the yellow uncut), and then I ONLY connected the Red wire, which is supposedly ground, sound still came out of my LEFT speaker? This is the part that I'm still a bit confused about.
 

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drinkmalk said:
Bear with me for asking a few more questions, but usually, the negative terminal (Red and Black in this case) are just grounds right? I mean that is why you connected those 2 to the Yellow wire. If they are ground, then that means they are at 0 volts. But, when I cut the, Red, Black, Green, and White wires (again note, I left the yellow uncut), and then I ONLY connected the Red wire, which is supposedly ground, sound still came out of my LEFT speaker? This is the part that I'm still a bit confused about.
hmmm...I'm really not a stereo guy, you should probably wait for Lisnup or cdstudio to chime in here. But, the way I see it is that each channel has it's own ground. In order to get better sound, they feed in another ground for both channels so that you get better grounding as it is probably from a different location in the car. That is also why you have a shielded casing with an exposed grounding wire.
 

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It is right that the OEM amp input does not use regular type of ground for their input.
That is the reason why if the +/- input pair of wires is connected to the external output L/R, the sound volume increases. Let's say there is 1V output for the L channel and 1V output for the right in the external source. Both channels share the same ground. Now, if their output is connected to the input +/- pair, it will be somewhat 1V+1V=2V.

That is very simplified and does not account for the fact when both channels will interfear with each other.


P.S.
That wiring diagram I scanned really goes around.
 
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