OnStar idea

Hey guys great forum here. I have a good challenge for you. I am using the hands free phone on my verizon account and love it, the 3 watts really helps. This is a 2006 sierra, I plan to put a better cell antenna on it. I can do that myself. I want to install a Nokia HSU-1. That's the privacy hanset. I know it will be easy to find and tap the mic wires. But I don't know how to get the audio because it comes out of the front stereo speakers. I was hoping to just intercept it at the radio but it uses the class 2 bus. Can you use the relays to switch the audio or will it degrade the sound quality? Should I just tap the front speakers or is there a way to tap the audio under the dash? Any other ideas?

Use a couple relays and the mute wire, when the mute goes low, it trigers the relay(s) to rout the phone audio to the front speakers, when ya hang up the relays de energize and radio audio back...Tire Proz Stillwater Mn

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