Use stock microphone with aftermarket bluetooth stereo?

[theophile]

I just got an '02 LS yesterday (absolutely love it so far!), and I'm planning to transplant my single-DIN JVC bluetooth head unit from my previous car into the LS. The JVC (like probably most bluetooth head units) comes with a small lapel-type microphone with a standard 1/8" stereo jack, and you're supposed to mount the mic somewhere and run the lead to the back of the HU.

My LS has that factory Motorola phone option with the flip-out bracket inside the arm rest, the overhead "SOS" and "Info" buttons, and a small microphone under a mesh cover on top of the steering column. I'm wondering whether I can use the factory microphone with the aftermarket HU. I presume that the factory mic is similar to the one included with the JVC in that it would just have +, -, and possibly shield/ground. If those leads run into the stereo wiring harness (or at least pass through there) I figure it should be as simple as isolating the wires and splicing a 1/8" stereo plug onto them.

Has anyone tried this, or does anyone know of a reason it wouldn't work?

 

[1LoudLS]

ive done it on other cars, sometimes it works well and sometimes it works terrible. it all depends on the mic itself and what kind of level it sends out. if the radio has a gain adjustment, that might help out to get it to match better.

 

[theophile]

Do you happen to have a picture or diagram of where the microphone wires are? I presume they would be in the radio harness somewhere.

 

[1LoudLS]

i would not expect them to be at the radio harness. most phone options are added on with an external (to the radio) module, the mic probably runs to that module and then that module sends the audio from the phone call to the radio through the harness.


I can say with some great certainty that one of the places the wires are located would be at the mic itself which as luck would have it is pretty close to the radio.

 

[theophile]

Okay, I have pulled out the factory microphone from the steering column. It's got a lead about 6" long and then a simple 2-pin connector:



Pin 1 is red, and Pin 2 is black and what appears to be shield twisted together:



I wanted to test it out before cutting any factory wires, so I grabbed a stereo 1/8" to RCA patch cable, cut off the RCA plugs, stripped back the wires, and inserted the bare wires into the mic connector in the way it looks like they would go: Red wire from patch cable to red pin in mic, and white wire plus both shields to the black/shield pin in the connector. I verified with the continuity setting on a multimeter that the rings on the 1/8" plug connect through to the appropriate pins on the back of the connector. But when I plug the contraption into the mic jack for my computer to test, I get no audio.

What am I missing? The mic internals include a PCB that's a little larger than I would expect for a simple microphone. Maybe this needs to get power over the wire too?