Mute Signal Circuit between Stereo Component Amplifier Assembly and Navigation ECU: Description
WARNING: This page is about a different car, the 2007 Lexus SC 430. However, it is still accessible from the selected car via links, so may be relevant.
Mute signals are sent via the navigation amplifier to the stereo component amplifier to mute noises that occur when muting the sound source. If the navigation system is available, the mute signal also mutes CD audio, etc. when the navigation system's voice guidance is on.
If the circuit is open: 1) noise will occur when the sound source is changed, and 2) if the navigation system is available, CD audio, etc. will not mute while the voice guidance is on.
If the circuit is shorted: 1) even if the amplifier is functioning properly, no sounds or only barely audible sounds will be output.