Radio/Stereo: Description and Operation
AUDIOThere are four different system combinations available on the LH models. They are a Base, Midline, Infinity I, and Infinity II system.
Fig.1 Radio Sales Code - Typical:
All factory-installed radios are readily identifiable by a three-digit alphabetical sales code, which is imprinted on the face plate lens just below a Pentastar logo.
BASE SYSTEM The Base System includes:
- AM-FM stereo radio with cassette player.
- Two 6.5 inch round, full-range speakers in the front doors.
- Two 6 x 9-inch, full-range speakers mounted in the rear shelf panel.
MIDLINE SYSTEM The Midline System includes:
- AM-FM radio with cassette player.
- AM-FM stereo radio with CD/cassette.
- A compact 120 watt power amplifier with four output channels.
- Two 2.5 inch, round single-cone speakers in the lower front corners of the front door windows.
- Two 6.5 inch, round single-cone speakers in the front doors.
- Two 6 x 9-inch, coaxial speakers mounted in the rear shelf panel.
INFINITY I SYSTEM The Infinity I System includes:
- AM-FM stereo radio with cassette player and 4 disc in-dash CD changer.
- AM-FM stereo radio with CD and cassette player.
- A 240 watt Infinity power amplifier with six output channels
- One 2.5 inch, round single-cone, spatial imaging speaker in the center of the instrument panel.
- Two 2.5 inch, coaxial speakers in the lower corners of the front door windows.
- Two 6.5 inch, round single-cone speakers in the front doors.
- Two 6 x 9-inch, single-cone speakers mounted in the rear shelf panel.
INFINITY II SYSTEM The Infinity II System includes:
- AM-FM stereo radio with cassette player and 4 disc in-dash CD changer.
- A 360 watt power amplifier with nine output channels, one for each speaker location.
- One 2.5 inch, round single-cone, spatial imaging speaker in the center of the instrument panel.
- Two 2.5 inch, coaxial speakers in the lower corners of the front door windows.
- Two 6.5 inch, round single-cone speakers in the front doors.
- Two 6 x 9-inch, single-cone speakers mounted in the rear shelf panel.
- Two 2.5 inch, round speakers mounted in the rear doors.
For operation of the factory installed standard and optional radios with cassette or compact disc player, refer to the Sound Systems Operating Instructions in the Owners Manual supplied with the vehicle.
The vehicles are shipped with fuse 13 removed from the junction block. The fuse replaces the Ignition-Off Draw (IOD) connector. Fuse 13 is a ten amp fuse. When removed, it prevents the battery from discharging during storage.
Fig.12 Midline/Infinity Remote Amplifier Location:
AMPLIFIER
Midline And Infinity I System
The amplifier is located in the right front Cowl panel.
Infinity II System
The amplifier is located beneath the trunk liner covering the right quarter inner panel.
For specific operation of each individual system, refer to the vehicles owners manual, Audio System Operation.
When the radio system is ON, and all or some speakers are not operating or have a noise distortion refer to the diagnostic tests.
CD CHANGER
The 4 Disc In-Dash CD Changer (if equipped) is located in the existing cubby bin. It is a cartridgeless changer controlled by the radio and allows the occupants to load up to four discs at one time.
Due to its compact design, the CD changer can only carry out one operation at a time. For example, you can not load a new disc while playing another at the same time. Each operation happens sequentially.
The radio unit provides control over all features of the CD changer with the exception of the CD load and eject functions, which are controlled by buttons located on the front of the CD changer. All features you would expect, such as Disc Up/Down, Track Up/Down, Random and Scan are controlled by the radio, which also displays all relevant CD changer information on the radio display.
The CD changer contains a Load/Eject button and an indicator light for each of the four disc positions. The individual light indicates whether a CD is currently loaded in that particular chamber of the CD changer. Pressing the individual Load/Eject button for a particular chamber will eject a disc currently present in that chamber. If the chamber is currently empty, actuating the Load/Eject button will position that chamber to receive and load a new disc in that chamber.
RADIO NOISE SUPPRESSION GROUND STRAP
Some components used on the vehicles are equipped with a capacitor to suppress radio frequency interference/static.
Ground straps are mounted from the engine to each shock tower. The ground straps should be securely tightened to assure good metal to metal contact.
Capacitors are mounted in various locations internal to the generator, instrument cluster and windshield wiper motor.
Ground straps conduct very small high frequency electrical signals to ground and require clean large surface area contact. The radio grounds to the floor pan through a ground strap which bolts to the back of the radio from the instrument panel wire harness.
Rear Defogger / Antenna Module:
REAR WINDOW ANTENNA MODULE
The integrated rear window antenna incorporates the rear window defogger and a electronic module to receive radio signals. The module is located in the right C-pillar behind the trim panel.
The AM and FM signals are received via isolated unheated lines along the top of the rear window.
NOTE:
- If aftermarket window shading is added, it cannot be of the metallic type. Metallic type window shading can cause poor radio reception.
- If an accessory cellular phone glass mount antenna is installed, it should only be installed so as to avoid contact with any of the rear glass grid lines.
Fig.21 Remote Radio Switches:
REMOTE SWITCHES
Remote radio control switches are rocker-type switch units are mounted in the upper spoke covers of the rear (instrument panel side) steering wheel trim cover. The switch unit on the left side is the seek switch and has seek up, seek down, and preset station advance switch functions. The switch unit on the right side is the volume control switch and has volume up, volume down, and mode advance switch functions.
The two remote radio switch units are each retained in a mounting hole located on opposite sides of the rear steering wheel trim cover by four integral snap features. A plastic bracket on the back of each switch unit provides additional support for the unit by extending towards the center of the steering wheel where it is clamped between the steering wheel armature and the steering wheel rear trim cover mounting boss by the trim cover mounting screw.
The two remote radio switch units share a common steering wheel wire harness with the vehicle speed control switches. The steering wheel wire harness is connected to the instrument panel wire harness through the clockspring.
The six switches in the two remote radio switch units are normally open, resistor multiplexed momentary switches that are hard wired to the Body Control Module (BCM) through the clockspring. The BCM sends a five volt reference signal to both switch units on one circuit, and senses the status of all of the switches by reading the voltage drop on a second circuit.
When the BCM senses an input (voltage drop) from any one of the remote radio switches, it sends the proper switch status messages on the Programmable Communication Interface (PCI) data bus network to the radio receiver The electronic circuitry within the radio receiver is programmed to respond to these remote radio switch status messages by adjusting the radio settings as requested. For diagnosis of the BCM or the PCI data bus, the use of a DRB III scan tool and the proper Body Diagnostic Procedures are recommended.
For more information on the features and control functions for each of the remote radio switches, see the owner's manual in the vehicle glove box.
AUDIO SYSTEM
There are radio systems available that communicate on the PCI bus. They use the bus for three reasons. First is to communicate trouble codes to the body control module, second is to control the remote radio switches located on the back of the steering wheel, and third is for use with the driver memory selection system. The radio stores two sets of station presets and can be recalled by pressing the optional memory select button (located on the drivers door). The midline will have 6 speakers and a 120 watt external amplifier. The Infinity I will have 7 speakers and a 240 watt external amplifier or with a indash 4-disk CD Player. The Infinity II will have 9 speakers and a 360 watt external amplifier with indash 4-disk CD Player. Depending on the manufacturer, some systems have a Front/Rear channel system and others have a Left/Right channel system.
When troubleshooting output shorts or "output" error messages, the following applies:
On radios with out an external amplifier, the term output refers to the path between the radio and the speaker. This type of circuit can be monitored all the way through the speaker connections by the radio assembly. When the radio displays a shorted output DTC with this type of system, the speaker, radio, or wiring could be at fault. The output DTC could refer to a front or rear output or a left or right output. The reason for the difference is the pairing of the output sections of the radio. Some are paired left and right, others are paired front and rear.
On radios with an external amplifier the term "output" refers to the circuit between the radio connector and the amplifier. The radio is capable of monitoring only this portion and can tell nothing about the circuit between the amplifier and the speakers. Consequently, a shorted output DTC on this type of system would only refer to this circuit. A faulty speaker could not cause this DTC.
These radios can be controlled via remote radio switches (optional). These switches are located on the back side of the steering wheel. They control volume, preset bank selection, seek and scan functions.
These functions are inputs to the body controller and can be read with the DRBIII(R) under "body" systems, sensor displays. The switches are a multiplexed signal to the BCM. The remote radio control circuit is a five volt line that is pulled to ground through different value resistors built into the switches. This causes a voltage drop to be seen by the body controller and it sends a specific message to the radio on the PCI bus line. The radio then responds to the message.
This circuit is fairly simple to troubleshoot. The circuit must be complete from the switches in the steering wheel to the BCM. The ground must be complete so that the switches can cause the voltage drop for the BCM to see. The circuit passes through the clockspring so continuity throught this device must be verified.
The new in-dash CD-changer is designed to fit into the existing cubby bin in the center stack. This new cartridge-less CD-changer is controlled by your radio, and allows you to individually load up to four discs at one time. However, due to its compact design, the CD-changer can only carry out one operation at a time. For example, you can not load a new disc while playing another at the same time. Each operation happens sequentially.
The radio unit installed with your system provides control over all features of the CD-changer with the exception of the CD load and eject functions, which are controlled by buttons located on the front of the CD-changer. The radio also supplies the power, ground, PCI Bus, left and right speaker output thru a single DIN cable. All features you would expect, such as Disc Up/Down, Track Up/Down, Random and Scan are controlled by the radio, which also displays all relevant CD-changer information on the radio display.
The CD-changer contains a Load/Eject button and an indicator light for each of the four disc positions. The individual light indicates whether a CD is currently loaded in that particular chamber of the CD-changer. Pressing the individual Load/Eject button for a particular chamber will eject a disc currently present in that chamber. If the chamber is currently empty, actuating the Load/Eject button will position that chamber to receive and load a new disc in that chamber.