Basically what the title says. I want to upgrade my head unit so I bought my brother's old one, since he totaled his car not too long ago and bought another with an aftermarket unit already in it. When he went to the lot to pull stuff he wanted form the car, he only got the head unit and not the wire harness or the other amenities that go with it (he didn't know he'd have to pull those too, as I was the one who installed it). I've already bought the wiring harness, but now all I'm missing is the mic for the hands free system. My question is if I still need to buy that mic or can I still use the OEM one without the OEM head unit?

 

It's a complicated question. You have an '06 sedan or coupe? That may have been the first year of the built-in hands free stuff for our cars so it was an early implementation and not all that great if I remember.

The short answer is yes, there is a built-in mic up near the map lights and the shielded audio cable runs to the telephone unit in the trunk (at least on sedans). But the mic unit itself has 6 wires connecting to it, two are audio, one is "VCC" (volume control??), one goes to the BCM, and one goes to the "illumination system", whatever that means... And that telephone / Bluetooth unit in the trunk works in conjunction with the OEM audio system, muting any other audio source for incoming calls, sending telephone audio through the car's speakers, receiving and translating voice commands, responding to the steering wheel buttons, etc...

If your new head unit has built in phone/bluetooth and all you need is a mic, it might actually be simpler to just buy one that will interface with it. That would likely sound better than the original too.

 

The factory mic is a powered unit, if I remember correctly. Most aftermarket headunits are a passive microphone setup.