The G35 audio unit has the capability to mute the forward speakers (but not the rear), and this function is used by the Nav system for voice commands.

Referring to the audio unit connector diagram shown, terminals 24 and 31 are inputs for the mute signal as follows:

24 (wire color: R/B): (+) Mute On
31 (B): ground

Terminals 30 and 32 are for the line audio from the Nav (or other source) as follows:

30 (wire color W/B): audio (-)
32 (L/W): audio (+) 1 Vpp

For those without factory Nav, installing this capability for cell phones, etc. seems straighforward. The difficulty is in accessing the back of the audio unit (see these involved instructions elsewhere under Sat radio cable install, etc.).

For those with factory Nav, some experimentation may be required to insure that the Nav voice system will operate simultaneous with another audio input (and mute signal). Caution is in order. You don't want to damage the Nav!

(This info was compiled from a schematic posted by NEXTMILL on FreshAlloy)

[EDIT: Schematic is here in pdf format.]

'04 G35S 5AT, Black Obsidian/Willow, Prem, Nav

175836-G35-jnct.jpg

 

Yup. I have been looking into devise such a 'mute' option from the Nav signal as well. I haven't been able to continue work on it due to lack of free time. I will resume the project when I find more time.

Clint (THX723)

 

I've finally made the mute function work with my cellphone handsfree (which is a Cellport)!!

There was one "minor" problem, however. The audio unit is set up to mute upon a +12V signal to terminal 24 as indicated. But most devices that send mute signals (like my handsfree unit) are set up to provide a closed circuit to ground. In other words, the "mute" wire from the Cellport is normally an open circuit, but when the phone is active, the wire assumes ground potential. To make it work on the G35, a relay is therefore required. Any simple 12V type will do, as the currents are very small. You will have to wire (+) battery power and the device (ground) mute signal to the switcher side of the relay. On the power side, connect (+) battery and a wire to terminal 24 of the audio unit. When the ground signal is given, the relay switch closes and passes +12V to terminal 24. Instant mute!!

Keep in mind that only the front speakers are muted. This is the same behavior that the Nav voice has.

'04 G35S 5AT, Black Obsidian/Willow, Prem/Nav/Sat

 

I wanted a MUTE button as well (the RX-8 even has one I believe)... but if you just press the power button on the steering wheel, that pretty much IS the mute button. The system turns off. Hit it again, and the system comes back on. No biggie.

 

bamadog,

This isn't just about having a manual mute button (although I wish for that also). This function is for automatically muting the audio system when the cellphone is in use.

'04 G35S 5AT, Black Obsidian/Willow, Prem/Nav/Sat

 

gotcha, dog. I hear ya. A lot of times, my radio is so loud, I don't even hear my cell phone... and my system is shielded so I don't hear any interruption in my broadcast either (static noises you hear in non-shielded systems). Automatically, huh? Who knows......