How to: DIY OEM mic retention 2014 Carplay & Android Auto

Just wanted to put this out there. I made my own plug and play harness for my head unit upgrade. I installed a Kenwood dnr1007xr recently. Pics at the end.

I had an oem non-jbl unit with a 28 pin connector. This should also work with other connectors with the same mic. You just need to know the which pins provide power, ground, and mic output. I tested this with android auto and an iPhone 12 with carplay. The people I called said I came in clear with both android (Samsung S20) and the iPhone 12. They do get an echo on their end, but I think that has more to do with how well the mic is picking up their voice from my speakers and sending it back through.

Items used:

I bought the harness off ebay. $14 shipped. It's the same harness used to add an aftermarket rca back up cam.
https://www.ebay.com/itm/3544367254...XtUwZXuSpW&var=&widget_ver=artemis&media=COPY

3.5mm jack with pigtails from Amazon. You can get a 2.5 if you have a pioneer, but make sure the noise filter is also 2.5mm.

3.5mm noise filter from amazon. Cable Matters Ground Loop Isolator 3.5mm Noise Isolator Hum Eliminator for Car Audio and More

$12 Cable Matters Ground Loop Isolator 3.5mm Noise Isolator Hum Eliminator for Car Audio and More

https://www.amazon.com/dp/B08G9J74VX

Voltage reducer aka buck converter.
Valefod 6 Pack LM2596 DC to DC High Efficiency Voltage Regulator 3.2-35V to 1.25-30V Buck Converter DIY Power Supply Step-Down Module

$11 Valefod 6 Pack LM2596 DC to DC High Efficiency Voltage Regulator 3.2-35V to 1.25-30V Buck Converter DIY Power Supply Step-Down Module

https://www.amazon.com/dp/B076H3XHXP

18 GA wire.
Multimeter with gator clips
2 gator clips to connect to 12v source
---------------

Instructions:
28 pin harness:
Find the pins 4, 5, 6, 18, & 19 on the harness. You will be cutting those. The harness that you want to make the connections on will be the side that plugs into the truck side harness. It will have male pins inside the harness.
Pin 4 is +12v ign (5amp fused)
Pin 5 is Mic+ solder to 3.5mm red wire on pigtail.
Pin 6 & pin 18 is soldered together and then attached
pin 19 is Mic- solder to Black wore on 3.5mm pigtail

Buck converter:
It will be clearly marked with V-in and V-out. Connect the set of gator clips to a 12v battery. Connect your multimeter, set to 12v+ dc to the output. There is a small brass flat head bolt on the converter that you turn. Turn until you see movement on the multimeter. If you see it go up, turn it I think other direction until you get to 5v. This doesn't need to be exact. I got mine set to 5.03v.

Once you have the screw set, add a dab of liquid electrical tape to the screw's side and pot body. Once it dries, itll keep the screw from getting accidentally turned. Solder 2 to 3 feet of leads on both in and out connections. The V-in leads go to a +12v ign source. I have a fuse box inside my center console close to my shifter that I tap from. The out leads get soldered to your #6/18 and #4 leads off the harness.
You will want to put the converter into a project box so it doesn't short.

Recommendations:
1.) Use a straight 3.5mm jack instead of the 90 deg one like I did. Add 1-2 feet of wire to the pigtail so the noise filter can be tucked away instead of sitting behind the head unit. There's almost no space back there.

2.) Noise filter comes with a short 90 deg 3.5mm cable. Buy one that is 2-3 feet so you can tuck the noise filter away.

I run separate power sources for most everything. I would recommend attaching the Buck converter to its own power source instead of the wires for the radio.

 

Ok sweet. Seems doable (obviously since you did it!)

End result is a little bulkier than I was hoping for, but I like how you got the noise isolator in; I was looking at those on Amazon. I was also looking for a dongle that would help with noise cancellation presumably using two mics but I couldn’t find any.

How’s the sound quality? Would you do this again if you had the opportunity or just run a standard 3.5mm mic cable?

 

I agree on the bulk. What I would do is extend the pigtail on the 3.5mm mic so that the noise isolator can be tucked away instead of being behind the radio. I would say 2' of wire. Obviously, you will get a 1m 3.5mm jack to plug into the noise isolator to hu.

My wife says she can hear me just fine. No issues with sound at all. There is an echo on her end where she is hearing herself. This issue is more to do with the radio not being able to cancel the echo and not the mic. I also tried using the enfig mic connected directly to the radio to see if the echo would go away and it did not. So this DIY has no bearing on the echo issue for the recipient.

 

Just to update. Making and taking calls through Android Auto works without any echo on either end. I think the issue before was that I was making calls using the BT function of the head unit and the AA was also active, so it was creating some kind of double signal. When I used AA to take a call from my wife, she said it was so clear that she could hear my engine (I was accelerating from a stop light). She said there was no echo, so it's more of a head unit/ BT issue.