# How to connect aftermarket headunits to the OEM hands free microphone



## StLouisCPhT (Sep 13, 2015)

*For 2011-2015 Cruzes and 2016 Cruze Limiteds made in the United States and Australia only.*

I decided to move this how-to into it's own thread as it is relevant for all aftermarket systems, not just the one I installed.

You will need the following items:

1) 2.5mm or 3.5mm mono right angle plug to bare end microphone cable. The size plug needed will depend on your head unit. I recommend a 6 ft cable be used as this will give plenty of length to work with. You can also just cut the microphone that came with the head unit off it's cable if you don't think you'll move the new head unit to a different vehicle later.

2) Terminated lead (GM Part Number 13579944).

3) T-Tap connector. The type needed will depend on step 4. Amazon Link

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Step 1 - Plug the cable into your head unit then run the other end through your center console so it comes out the back by the BCM. Make sure the cable is loose and not binding or rubbing against anything.

Step 2 - Remove the sound insulator from under the glove compartment. This is held in place by 2 bolts (9/32) in the front, right below the glove compartment door. Once you have removed the bolts, it will drop onto the floor (if it didn't already start doing that). Put the insulator someplace out the way for now.

Step 3 - Loosely run the microphone cable across to the right side kick panel. once you do that, add another 12 inches of length and cut off the excess.

Step 4 - Reach up behind the dash above the RH kick panel. This is where the onstar module is located. You will need to unplug the 2nd connector from the top and pull it down. If there is not enough length, you might need to also remove the top connector. Once you have the connector low enough to work on, verify if a wire is already installed in the #6 position - looking at the side the wires plug into, this will be the top row on the right side. If it is not there, install the terminated lead you purchased in #6.

Step 5 - Use the T-Tap connector to splice your microphone wire to the #6 wire.

Step 6 - This is the most important step. Test the connection by triggering Siri/Voice Control on the new head unit. This will be a lot easier with Siri... I have not used Android Auto so I don't know if it gives a visual indication of audio input received. Do not say anything, just watch your display to see if there is any activity. The less shown the better as this means that the system is picking up very little ambient/electrical noise and you will have a clear hands free audio signal. (My installation shows a perfect flatline in Siri when tested, even with my vehicle running.) The system will probably timeout while you are checking this. If it does, trigger Siri/Voice Control again and try a command to verify that it is received and understood.

Step 7 - If you have a clear audio channel and your commands are received and understood, then tuck the cable up out of sight in the dash and reinstall the sound insulator.

Thanks go to @dhpnet for providing the original diagram and Onstar pinout information as part of the Mylink retrofit project.


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## Amycolo1 (Nov 18, 2020)

Would you mind sharing the diagram/schematic/pin out, please?


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## Amycolo1 (Nov 18, 2020)

Also, mic cables have 2 wires. One of them, you’re hooking into the #6 hole of the factory connector. What are you hooking the 2nd wire to?


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## mail.djain (Jan 14, 2020)

Hi Were you able to figure out the connection, I am trying do the same, Where does the second wire from Mic go ? Any pictures of module ?


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