Dodge Ram Truck 1500-2500-3500. Manual - part 270
SUBWOOFER – QUAD CAB
1. Position subwoofer to vehicle.
2. Connect electrical harness connector.
3. Install and tighten mounting fasteners.
4. Lower seat.
5. Connect battery negative cable.
SUPPRESSION COMPONENTS - RADIO NOISE
DESCRIPTION
Radio noise suppression devices are Installed on this vehicle. Radio Frequency Interference (RFI) and ElectroMag-
netic Interference (EMI) can be produced by any on-board or external source of electromagnetic energy. These elec-
tromagnetic 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. External
radio noise suppression devices that are used on this vehicle to control RFI or EMI, and can be serviced, include
the following:
•
Engine-to-body ground strap - This length of braided ground strap has an eyelet terminal connector crimped
to each end. One end is secured to the engine cylinder head(s). The other is secured to the plenum at the
exhaust heat shield forward/outer attaching stud.
•
Resistor-type spark plugs - This type of spark plug has an internal resistor connected in series between the
spark plug terminal and the center electrode to help reduce the production of electromagnetic radiation that
can result in radio noise.
OPERATION
There are two common strategies that can be used to suppress Radio Frequency Interference (RFI) and Electro-
Magnetic 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 recep-
tion 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
8A - 82
AUDIO - SERVICE INFORMATION
DR/DH