Sound Signal Circuit between Navigation Receiver Assembly and Stereo Jack Adapter: Description
WARNING: This page is about a different car, the 2008 Toyota Tundra. However, it is still accessible from the selected car via links, so may be relevant.
The stereo jack adapter sends an external device sound signal to the navigation receiver through this circuit. The sound signal that has been sent is amplified by stereo component amplifier, and then is sent to speakers.
If there is an open or short in the circuit, sound cannot be heard from the speakers even if there is no malfunction in the stereo component amplifier, navigation receiver, or speakers.