Just wanted to share the pinout for the aux input on the NTG1 COMAND units in case anyone may find it useful. Knowing a bit about audio electronics I was able to take an educated guess that turned out to be right. On a typical three wire 3.5mm stereo connection, there is a left channel, a right channel, and a shared ground. The ground is usually uninsulated or even tied to the shielding of the cable. That is the case for the cable that runs from the back of the headunit into the glove box aux port, but on the last approx. 2 inches before the connector on the headunit side the three wires break out individually which makes it super easy to work with. They are as follows:

Ground - center wire in the connector, which has clear insulation
Left channel - white insulation
Right channel - brownish insulation (maybe was red at one point?)

Verified these channels with an audio test track that had left only and right only content and it is correct.

I recently did a custom stealth install of an Amazon Echo Auto in my ash tray area and rather than running the wire into the glove box I wanted to relocate the aux input, but I also wanted to include a ground loop isolator (noise filter) to cut out the annoying buzzing that I was hearing when the Echo was plugged in but nothing was playing. I accomplished both these goals by using a Pyle Ground Loop Isolator I got from Amazon (note: not an affiliate link, just sharing what I bought) and desoldered the output leads from it and then soldered the cut leads from my car's aux input wiring as shown in the following pictures.





The hardest part about this install was working up the courage to take a pair of scissors to my car's Aux wiring harness. This was my first time soldering and it was super easy! I don't have a desoldering tool, just a normal soldering iron, and I had no problem getting the old wires off the board by just heating the solder and pulling from below until they popped out. I was able to get the new wires in by heating the solder and pushing the new wire in from below and then once in I added a bit of new solder (important to use solder rated for electrical use) to secure them and make a good connection. I did not take any pics of my work, but my solder joints turned out looking pretty much like the other ones on the back of the board.

After all that work I was a bit disappointed that there is still an intermittant buzzing noise coming from the Echo but I believe that must have something to do with the Echo itself. When there is music or anything else playing it goes away completely and the audio signal sounds very clean, though not quite as detailed to my audiophile ears as when listening to the CD changer. I'm blaming that on the bluetooth compression and not any of the hardware involved, it's an inherent sacrifice of the format.

I also hardwired in a wireless charging mat in my upper center console and now I've got a completely wire-free integration of my phone in my car, allowing me to make and receive calls hands free, play music from my phone via bluetooth, and access all the features of Amazon Echo (including controlling my smart home devices from the car, which my wife loves and which I find very amusing lol) all for a total cost of around $100 and a few hours of meticulous work. Also used some felt tape and foam weatherstripping to completely rattle-proof my center console while I had it apart. Need to do that to a couple other areas of my interior, now that it's so quiet I'm noticing other small squeaks and rattles. Anyway I'll post more pics of my install if anyone is interested.

 

Post em up

 

Okay, here you go!



With the ashtray closed, you cannot see anything. The Echo device actually picks up my voice commands over 90% of the time with the ashtray door closed, and I can keep the door closed to talk on the phone also. I tried it both ways with my wife and she said with the door closed she hears less road noise but my voice isn't as loud, so depending if you're getting the "too much road noise" complaint or "I can't hear you" complaint, you can fix it either way.




With the ashtray open, you can see the Echo Auto. It's got 8 microphones in it and in my normal seating position I can see all of them with the ashtray door open. I'm assuming this means they can all hear me. I can also see the reflection of the blue or green light strip on it bouncing off the right side of the ashtray and my front passenger can see just a bit of it directly from their seat.




With all the fooling around with the ashtray during this mod, I burned out the bulb for the light around the power port. It still works to power my USB charger though, which is pretty redundant but looks nicer than an empty hole or a plug.




I drilled two holes in the very back of the ashtray holder, one for the micro USB power cable and one for the audio jack. If I ever wanted to undo this mod, I could just put the ashtray back in and you wouldn't be able to tell anything ever happened. The Echo device is held in by 3M double sided trim tape.




Here is my wireless charging pad in the center console. It fits perfectly between the left wall of the compartment and the part that sticks out with the two SOS buttons on it.




I got this off of Amazon also, it's available in gold or black but the gold one was on sale. Actually I'm not seeing the gold one on there anymore so maybe it was a clearance sale. Anyway is the link (not an affiliate link, just sharing what I bought) in case you want one.




It comes with a very thin USB cable attached to it, and the whole pad itself is semi-flexible so it lays down nice and flat. I notched the front edge of the false floor of the upper center console compartment very slightly to be able to route the cable under the false floor and down into the console, and I secured the pad to the false floor with some rubber cement. If I ever decided to reverse this mod, the notch is so small no one would notice and the rubber cement peels off easily.




The charging pad is covered in leather and the edges are very flexible so it was easy to get that cable to go straight down and tuck the pad nice and tight into the space where it sits.




I routed the USB cable from the upper compartment to the space under the lower compartment through the center of one of the coiled wires. I did this with the armrest locked fully vertical so that there would be plenty of slack for it to open and close.




The wire is very thin as you can see and is barely noticeable. Beneath the false floor in the lower compartment is a space for all of the wires that run to the rear A/C controls and the rear power socket. I used vampire taps to connect my power supplies to the wire running to the rear power socket.

is a link to the power supplies I used. One for the charging pad and one to run the Echo Auto. These support the Quick Charge 3.0 protocol which was necessary for the charging pad to work. I put foam weatherstripping on either side of each of them and placed them under the part of the center console that holds the cupholder. This not only secures them in place but it helps eliminate sqeaks and rattles of the cupholder holder, which was the main source of noise coming from my center console.

 

NICE!!!

 

@charlesb2003 VERY NICE!!!! I have the Echo Auto in a LandCruiser and love it (I didn't think I would use it, but I use it all the time), and have been wanting to add it to our E320 and SL550, but couldn't find a good place to put it. Putting it in the ashtray seems like a great idea? How did you power the Echo? I'm assuming you just tapped some power wires behind the ashtray? Did you use a USB adapter behind the ashtray?

Lee

 

I used two of installed inside the center console, underneath where the cupholder goes.


I cut the fuse part off and excess wire off, since the circuit I tapped is already fuse protected. I used vampire taps to tap into the 12v line in the center console going to the rear 12v power port in that pop out drawer. The usb connection for the charging pad is accessible underneath the false floor in the lower center console compartment, and the usb connection for the Echo Auto is right behind the cigarette lighter compartment. I used a short micro usb cable with 90 degree bends to connect it so that there would not be excess length of usb cable hanging out inside the center console.

I wish I had taken more pics of all that during the process. If I ever have to take my center console apart again I'll snap a few pics.