I'm surprised that my LS430 factory navigation doesn't mute the stereo volume when giving turn-by-turn directions. Do other Lexus models (IS,ES,GS,GX,LX) mute the stereo when the navigation speaks?

Most OEM navigation systems provide this kind of functionality. I've done research into the LS430 navigation wiring diagram and see that there is a mute wire (NVMU) between the navigation ECU and stereo component amplifier. Anybody have ideas why this wire is in place if there is no navigation mute function on the LS430?

 

Looking and testing this further, the only LS speaker that gets muted is the front left, but this still doesn't explain why there is a mute wire between the navigation and component amplifier.

 

I believe when the radio changes modes (from AM to CD, FM to tape, etc.) it will briefly instruct the amplifier to mute the speakers to avoid popping noises. However, since the front left speaker is connected directly to the navi and not the amplifier, the mute signal has to be also passed to the navi ECU.

My best guess anyway.

 

My gs only mutes the front Left as well.

 

Front left only on my 98 LS400.

 

jp82729, I bet your right. The mute wire in question here is for changing sources and such.


If I find a way to mute *all* speakers when the navigation speaks using a wire jumper would you guys be interested? How this could be done is the amplifiers telephone mute wire could be routed to the navigation ECU mute wire (provided they have the same polarity or function, for example - or +12 when navi speaks). By turning the voice guidance volume OFF this should stop the navi from being able to mute the speakers. Or putting a switch in between the jumper to turn this function OFF will make it operate like factory design again.