Circuit/System Description
WARNING: This page is about a different car, the 2015 Cadillac SRX. However, it is still accessible from the selected car via links, so may be relevant.
The media disc player is a separate component from the radio. The media disc player receives power, ground and serial data from the vehicle harness. The media disc player receives control information and outputs audio to the infotainment system over the MOST bus.
The eject switch for the media disc player is a touch type switch that is part of the instrument panel multifunction switch assembly. The switch assembly receives battery voltage and ground from the vehicle harness. A discrete eject signal circuit is provided to the switch assembly from the media disc player. When the switch is touched, the signal circuit is pulled low through the assembly and the media disc player ejects the disc.