Circuit/System Description
WARNING: This page is about a different car, the 2016 Cadillac CT6. However, it is still accessible from the selected car via links, so may be relevant.
When the radio/amplifier is on, a discrete 3 V signal is supplied on the control circuit to each secondary audio amplifier. This signal is used to control the power state of the component. Each secondary audio amplifier controls the audio for its appropriate speaker.