My car has a factory fitted microphone for the car's original bluetooth phone system. I am removing the system and replacing with a android based head unit. The head unit comes with a aftermarket 3.5mm audio jack microphone but i want to see if i can use my factory microphone instead, specially since the wires go back to the radio connector. I've looked at the cars wiring diagram and have located the mic+ and mic- terminals on the now unused connector, but when i connect a 3.5mm jack to this, I just dont get anything. I tried hooking it up to my laptop and i cannot get the signal coming from that microphone at all. I've attached a picture of the wiring diagram below. If anyone can help, that would be great. It appears that the factory mic has some sort of ACC power and maybe it was originally getting ACC power from the original stereo and now that the stereo isn't connected then it's not getting any ACC power anymore. So maybe i need to hook up 12v ACC power to that ACC pin of the mic?

 

So i located the pinout for the terminals. It appears the purple pin 9 is power for the microphone amp and it says 5V. So this means I need to supply 5V to that pin for the mic to work

 

I'm about to attempt the same thing. Did it work for you?

@john2k

 

It has 2 signal wires, ground and power. Some sort of balanced & powered microphone circuit?

 

Is it possible to reach the microphone and gently open it up? Or hook up the factory HU again and probe those wires with a voltmeter or oscilloscope or audio amplifier?

 

You need a 12v supply to the ACC pin and ground, the output is from the mic+ & mic- terminals, these are fet mics and sometimes they have a balanced output .