Principles of Operation

PRINCIPLES OF OPERATION

Audio Unit
The audio unit can be operated while the key is in RUN or ACC. The accessory delay feature allows the audio unit to be operated for a preset period of time after the key is moved to OFF and a front door has not been opened. The audio unit sends AC voltage audio signals to the speakers or to the amplifiers, depending on vehicle configuration. The audio unit can produce its own DTCs, which can be communicated to the scan tool through the medium speed controller area network (MS-CAN), or can be retrieved through the audio unit self-test by simultaneously pressing presets 3 and 6.

Satellite Audio
The satellite audio system consists of a satellite radio receiver, a satellite radio antenna, and antenna cable. The satellite radio antenna receives digital audio signals and sends them to the satellite radio receiver, where the signals are converted and sent to the audio unit. The satellite radio receiver communicates via the MS-CAN.

Antenna - Late Build Fusion, Milan
The antenna receives AM/FM radio waves, and satellite audio signals (if equipped with satellite audio). The AM/FM antenna sends audio signals to the audio unit. The satellite radio antenna receives digital audio signals and sends them to the satellite radio receiver.

Antenna - MKZ and Early Build Fusion, Milan
The antenna receives both AM and FM radio waves. The antenna is built into the rear window glass and has a module to interpret the audio signals. The audio signals are then sent to the audio unit through the antenna cable. If equipped with satellite audio, the satellite radio antenna is mounted to the roof. It receives digital audio signals and sends them to the satellite radio receiver.

Subwoofer
The subwoofer speakers are powered by the subwoofer amplifier (Audiophile) or by the THX(R) amplifier (THX(R) only). The enable/clip detection circuit carries out 2 functions: to turn the amplifier on, and to indicate to the audio unit when the subwoofer output distortion signal reaches a damaging level. The audio unit then clips the audio output signal to prevent damage to the subwoofer.

THX(R) Audio System
The THX(R) audio system provides theatre quality sound in the vehicle. Audio signals are sent to the THX(R) amplifier, which processes the audio signals and sends them to the 12 speakers: 4 door speakers, 2 tweeter speakers, 3 front/center speakers, 1 rear/center speaker, and 2 subwoofer speakers.

Navigation
The navigation audio unit generates a display on a video screen. When an on-screen menu key is pressed, a new screen is displayed corresponding to the key that was pressed. The navigation audio unit is available with the Audiophile (late build) or THX(R) sound systems.

Steering Wheel Controls
The steering wheel controls consist of a series of resistors. Each steering wheel control switch function corresponds with a specific resistance value within the switch. When a switch is pressed, the audio unit monitors the change in reference voltage to determine the requested function.

Audio Input Jack (Late Build)
The audio input jack allows for a portable MP3 player to be connected to the vehicle audio system. When a portable MP3 player is connected, audio from the MP3 player can be played through the vehicle speakers.

Noise Suppression Equipment
The radio frequency suppression equipment reduces interference transmitted through the speakers by the engine ignition and electrical systems. When installing any new radio suppression equipment components, make sure that a good contact is made at all connections.