Dodge RAM TRUCK 1500 1995 Service Manual page 440

B R — AUDIO SYSTEMS 8F - 1
C O N T E N T S
page page
DIAGNOSIS 2 SERVICE PROCEDURES 6
GENERAL INFORMATION 1
G E N E R A L
I N F O R M A T I O N
Following are general descriptions of major compo­
nents used in Ram truck audio systems. Refer to
Group 8W - Wiring Diagrams for complete circuit de­
scriptions and diagrams.
RADIOS
Radio options for the Ram track models include an
AM/FM, an AM/FM/cassette, an AM/FM/CD, or an
AM/FM/cassette with graphic equalizer. All receivers
are stereo Electronically-Tuned Radios (ETR) and in­
clude a clock function. For more information on radio
features, setting procedures, and control functions re­
fer to the Sound System manual. The Sound System
manual is included with the owner's manual in the
vehicle glove box.
IGNITION-OFF DRAW FUSE
All vehicles are equipped with an Ignition-Off Draw
(IOD) fuse that is removed when the vehicle is shipped
from the factory. This fuse feeds various accessories that
require current when the ignition switch is in the OFF
position, including the clock and radio station preset
memory functions. The fuse is removed to prevent bat­
tery discharge during vehicle storage.
When installing or removing the IOD fuse, it is im­
portant that the ignition switch be in the OFF posi­
tion. Failure to place the ignition switch in the OFF
position can cause the radio display to become scram­
bled when the IOD fuse is removed. Replacing the
IOD fuse will correct the scrambled display. .
The IOD fuse should be checked if the radio station
preset memory or clock functions are erratic or inoper­
ative. The IOD fuse is located in the fuseblock module.
SPE1IEIS
Speaker system options include two or four speaker
locations. On two-speaker systems, one full range
speaker is located in each door. Four-speaker systems
add one full range speaker in each B pillar.
The premium speaker option upgrades the speak­
ers in the above locations to Infinity models. The two
B pillar speakers are coaxial units and each front
door has two separate speakers, a woofer and a
tweeter. Each Infinity woofer features an integral
amplifier and frequency filter unit. The amplifier of
the radio is used to drive the tweeters at each
speaker location. The speaker-mounted amplifiers
drive the woofers.
FILTER CHOKE/SPEAKER RELAY
Models equipped with the Infinity premium speak­
ers use this choke/relay to control battery feed to the
speaker-mounted amplifiers. The choke/relay is
mounted to the center lower instrument panel brace
to the right of the knee blocker opening. The choke/
relay should be checked if there is a lack of bass and
low frequency response noted at all speakers.
ANTENNA
All models 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. The antenna ca­
ble has an additional disconnect at the right end of
the instrument panel near the cowl side panel to al­
low instrument panel installation and removal with­
out radio removal.
To eliminate 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 an­
tenna base and the radio chassis.
The factory installed ETRs automatically compen­
sate for radio antenna trim. Therefore, no antenna
trimmer adjustment is required or possible when re­
placing the receiver or the antenna.
RADIO NOISE SUPPRESSION
Radio Frequency Interference (RFI) and Electro-
Magnetic Interference (EMI) noise suppression is ac­
complished primarily through circuitry internal to
the radio receivers. These internal suppression de­
vices are only serviced as a part of the radio receiver.
External suppression devices that are serviceable
AUDIO SYSTEMS