Audio System & Video System: Overview Dodge Caravan IV

DESCRIPTION

An audio system is standard on this model. A rear seat video system is an available option. Several combinations of radio receivers are offered on this model. The audio/video system uses an ignition switched source of battery current so that the system will only operate when the ignition switch is in the RUN or ACCESSORY/ACCESSORY DELAY positions.

The audio system includes the following components

1. Amplifier
2. Antenna
3. CD changer (if equipped)
4. DVD player (if equipped)
5. Radio noise suppression components
6. Radio receiver
7. Speakers
8. Video screen (if equipped)

Certain functions and features of the audio/video system rely upon resources shared with other electronic modules in the vehicle over the Programmable Communication Interface (PCI) bus network. The data bus network allows the sharing of sensor information. For diagnosis of these electronic modules or of the data bus network, the use of a DRB III(R) scan tool and the proper Diagnostic Procedures information is recommended.

Domestic vehicles use a fixed-length stainless steel rod-type antenna mast, installed at the right front fender of the vehicle. The antenna mast is connected to the center wire of the coaxial antenna cable, and is not grounded to any part of the vehicle.

OPERATION

To minimize static, the antenna base must have a good ground. The coaxial antenna cable shield (the outer wire mesh of the cable) is grounded to the antenna base and the radio chassis.

The antenna coaxial cable has an additional disconnect, located near the right end of the instrument panel. This additional disconnect allows the instrument panel assembly to be removed and installed without removing the radio.

The antenna module is an electromagnetic circuit component designed to capture and enhance RF (Radio Frequency) signals in both the AM and FM broadcast bands. The antenna module is mounted to the right rear roof rail under the headliner. The module is grounded through the mounting bracket and fastener. The module has a two wire electrical connector that connects to the integral radio antenna, located on the right rear quarter glass. There is also an electrical connector for battery voltage and a coax cable connector.

The antenna module receives both AM and FM radio signals supplied by the side window integral radio antenna system and selectively amplifies them. The amplified signal is then sent through the body length coax cable to the radio input.

The 6 Disc In-Dash CD Changer (if equipped) is located in the instrument panel below the radio. The remote changer does not use a cartridge or magazine for the CD's. Up to 6 CD's can be directly loaded into this unit.

Due to its compact design, the CD changer can carry out only 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 Eject button, six disc buttons, an indicator LED for each of the six disc positions as well as an illuminated disc opening. The individual LED indicates whether a CD is currently loaded in that particular chamber of the CD changer. Pressing the individual button for a particular chamber, then the Eject button will eject a disc currently present in that chamber. If the chamber is currently empty, actuating the individual button will position that chamber to receive and load a new disc in that chamber.

Scheme 1

1. Disconnect and isolate the battery negative cable.
2. Remove screws holding CD changer. 1 - CD-CHANGER 2 - POWER OUTLET
3. Disconnect the wire connector from the back of the CD changer.
4. Remove the CD changer from the vehicle. (Scheme 1)

The DVD player (if equipped) is located in the instrument panel below the radio. The DVD player can hold one DVD at a time. Three RCA jacks on the front of the unit allow the use of MP3 players, video game systems or camcorders.

Scheme 2

1. Disconnect and isolate the battery negative cable.
2. Remove screws holding DVD player. (Scheme 2) 1 - DVD PLAYER 2 - POWER OUTLET
3. Disconnect the wire connector from the back of the DVD player.
4. Remove the DVD player from the vehicle.

The quarter glass integral antenna element is bonded to the right rear quarter glass and is replaced with the glass assembly only. (Scheme 3)

Scheme 3

The integral antenna receives radio frequencies and sends them to the antenna module for amplification.

Available radio receivers for this vehicle include

1. AM/FM/cassette/CD (RAZ or RBP sales code)
2. AM/FM/cassette/CD with rear audio (RBU sales code)
3. AM/FM/cassette (RBB sales code)
4. AM/FM/6-disc CD radio (RBQ sales code)
5. AM/FM/CD/Navigation (RB3 sales code)
6. AM/FM/CD with CD changer control (RBK sales code) export only
7. AM/FM/cassette/CD (RBY,RAD, or RBT sales code) export only

All radio receivers can communicate on the Programmable Communications Interface (PCI) data bus network.

The radio receiver operates on ignition switched battery current that is available only when the ignition switch is in the On or Accessory/Accessory Delay positions. The electronic digital clock function of the radio operates on fused battery current supplied through the IOD fuse, regardless of the ignition switch position.

For complete circuit diagrams, refer to appropriate SYSTEM WIRING DIAGRAMS article.

Radio noise suppression devices are factory-installed standard equipment on this vehicle. Radio Frequency Interference (RFI) and ElectroMagnetic Interference (EMI) can be produced by any on-board or external source of electromagnetic energy. These electromagnetic energy sources can radiate electromagnetic signals through the air, or conduct them through the vehicle electrical system.

When the audio system converts RFI or EMI to an audible acoustic wave form, it is referred to as radio noise. This undesirable radio noise is generally manifested in the form of "buzzing," "hissing," "popping," "clicking," "crackling," and/or "whirring" sounds. In most cases, RFI and EMI radio noise can be suppressed using a combination of vehicle and component grounding, filtering and shielding techniques. This vehicle is equipped with factory-installed radio noise suppression devices that were designed to minimize exposure to typical sources of RFI and EMI; thereby, minimizing radio noise complaints.

Factory-installed radio noise suppression is accomplished primarily through circuitry or devices that are integral to the factory-installed radios, audio power amplifiers and other on-board electrical components such as generators, wiper motors, blower motors, and fuel pumps that have been found to be potential sources of RFI or EMI.

There are two common strategies that can be used to suppress Radio Frequency Interference (RFI) and ElectroMagnetic Interference (EMI) radio noise. The first suppression strategy involves preventing the production of RFI and EMI electromagnetic signals at their sources. The second suppression strategy involves preventing the reception of RFI and EMI electromagnetic signals by the audio system components.

The use of braided ground straps in key locations is part of the RFI and EMI prevention strategy. These ground straps ensure adequate ground paths, particularly for high current components such as many of those found in the starting, charging, ignition, engine control and transmission control systems. An insufficient ground path for any of these high current components may result in radio noise caused by induced voltages created as the high current seeks alternative ground paths through components or circuits intended for use by, or in close proximity to the audio system components or circuits.

Preventing the reception of RFI and EMI is accomplished by ensuring that the audio system components are correctly installed in the vehicle. Loose, corroded or improperly soldered wire harness connections, improperly routed wiring and inadequate audio system component grounding can all contribute to the reception of RFI and EMI. A properly grounded antenna body and radio chassis, as well as a shielded antenna coaxial cable with clean and tight connections will each help reduce the potential for reception of RFI and EMI.

Scheme 4

Two rocker-type switches (if equipped) are mounted on the back (instrument panel side) of the steering wheel spokes. (Scheme 4) The switch on the left spoke is the seek switch and has seek up, seek down, and preset station advance functions. The switch on the right spoke is the volume control switch and has volume up, and volume down functions. The switch on the right spoke also includes a "mode" control that allows the driver to sequentially select AM radio, FM radio, cassette player, CD player or CD changer (if equipped).

These switches are resistor multiplexed units that are hard-wired to the Body Control Module (BCM) through the clockspring. The BCM sends the proper messages on the Programmable Communications Interface (PCI) data bus network to the radio receiver. For diagnosis of the BCM or the PCI data bus, the use of a DRB III(R) scan tool and BODY DIAGNOSTIC PROCEDURES are recommended.

The video screen (if equipped) is mounted on the headliner behind the driver and front passenger seat. Pressing the release button will allow the screen to be opened.

Operating instructions for the factory installed video screen can be found in the owner's manual provided with this vehicle.

Scheme 5

1. Disconnect and isolate the battery negative battery cable.
2. Remove the lens bezel.
3. Remove the rear console screws. (Scheme 5)
4. Remove the rear A/C trim bezel.
5. Disconnect A/C wire harness connector.
6. Remove remaining mounting screws.
7. Disconnect wire harness connectors.

See also:
• BODY DIAGNOSTIC PROCEDURES