2002 DODGE RAM manual radio set

OPERATION
Battery voltage is supplied to the CAB when a
speed of 15 miles per hour is reached. The CAB per-
forms a system initialization procedure at this point.
Initialization consists of a static and dynamic self
check of system electrical components.
The static and dynamic checks occurs at ignition
start up. During the dynamic check, the CAB briefly
cycles the pump and solenoids to verify operation. An
audible noise may be heard during this self check.
This noise should be considered normal.
If an ABS component exhibits a fault during ini-
tialization, the CAB illuminates the amber warning
light and registers a fault code in the microprocessor
memory.
The CAB monitors wheel speed sensor inputs con-
tinuously while the vehicle is in motion. However,
the CAB will not activate any ABS components as
long as sensor inputs indicate normal braking.
During normal braking, the master cylinder, power
booster and wheel brake units all function as they
would in a vehicle without ABS. The HCU compo-
nents are not activated.
The purpose of the antilock system is to prevent
wheel lockup during periods of high wheel slip. Pre-
venting lockup helps maintain vehicle braking action
and steering control.
The antilock CAB activates the system whenever
sensor signals indicate periods of wheel slip. Periods
of wheel slip occur when brake stops involve high
pedal pressure and rate of vehicle deceleration.
The antilock system prevents lockup during a
wheel slip condition by modulating fluid apply pres-
sure to the wheel brake units.
Brake fluid apply pressure is modulated according
to wheel speed, degree of slip and rate of decelera-
tion. Sensors at each front wheel convert wheel speed
into electrical signals. These signals are transmitted
to the CAB for processing and determination of
wheel slip and deceleration rate.
The ABS system has three fluid pressure control
channels. The front brakes are controlled separately
and the rear brakes in tandem. A speed sensor input
signal indicating a wheel slip condition activates the
CAB antilock program.
There are Two solenoid valves (Isolation and Dump
valve) which are used in each antilock control chan-
nel. The valves are all located within the HCU valve
body and work in pairs to either increase, hold, or
decrease apply pressure as needed in the individual
control channels.
During an ABS stop the ISO valve actuates, Stop-
ping anymore pressure build Ðup to the calipers.
Then the Dump valve dumps off pressure until the
wheel unlocks. This will continue until the wheels
quit slipping altogether.
DIAGNOSIS AND TESTING - ANTILOCK
BRAKES
The ABS brake system performs several self-tests
every time the ignition switch is turned on and the
vehicle is driven. The CAB monitors the systems
input and output circuits to verify the system is oper-
ating correctly. If the on board diagnostic system
senses that a circuit is malfunctioning the system
will set a trouble code in its memory.
NOTE: An audible noise may be heard during the
self-test. This noise should be considered normal.
NOTE: The MDS or DRB III scan tool is used to
diagnose the ABS system. For additional informa-
tion refer to the Antilock Brake section in Group
8W. For test procedures refer to the Chassis Diag-
nostic Manual.
STANDARD PROCEDURE
STANDARD PROCEDURE - RWAL SERVICE
PRECAUTIONS
The RWAL uses an electronic control module, the
CAB. This module is designed to withstand normal
current draws associated with vehicle operation.
Care must be taken to avoid overloading the CAB
circuits.In testing for open or short circuits, do
not ground or apply voltage to any of the cir-
cuits unless instructed to do so for a diagnostic
procedure.These circuits should only be tested
using a high impedance multi-meter or the DRB
tester as described in this section. Power should
never be removed or applied to any control module
with the ignition in the ON position. Before removing
or connecting battery cables, fuses, or connectors,
always turn the ignition to the OFF position.
CAUTION: Use only factory wiring harnesses. Do
not cut or splice wiring to the brake circuits. The
addition of after-market electrical equipment (car
phone, radar detector, citizen band radio, trailer
lighting, trailer brakes, ect.) on a vehicle equipped
with antilock brakes may affect the function of the
antilock brake system.
STANDARD PROCEDURE - BLEEDING ABS
BRAKE SYSTEM
ABS system bleeding requires conventional bleed-
ing methods plus use of the DRB scan tool. The pro-
cedure involves performing a base brake bleeding,
followed by use of the scan tool to cycle and bleed the
5 - 36 BRAKES - ABSBR/BE
BRAKES - ABS (Continued)

ing diagrams, proper wire and connector repair
procedures, details of wire harness routing and
retention, connector pin-out information and location
views for the various wire harness connectors, splices
and grounds. Following are general descriptions of
the remaining major components in the standard and
optional factory-installed audio systems.
OPERATION
See the owner's manual in the vehicle glove box for
more information on the features, use and operation
of each of the available audio systems.
CENTRAL TIMER MODULE
The high-line or premium Central Timer Module
(CTM) can also control some features of the audio
system when the vehicle is equipped with the
optional RAZ radio receiver and remote radio
switches. A high-line CTM is used on high-line ver-
sions of this vehicle. A premium CTM is used on
vehicles equipped with the optional heated seats. The
CTM combines the functions of a chime/buzzer mod-
ule, an intermittent wipe module, an illuminated
entry module, a remote keyless entry module, and a
vehicle theft security system module in a single unit.
The high-line or premium CTM also controls and
integrates many of the additional electronic functions
and features included on models with this option.
The RAZ radio receiver with a remote radio switch
option is one of the features that the CTM controls.
The CTM is programmed to send switch status mes-sages over the Chrysler Collision Detection (CCD)
data bus to control the volume, seek, and pre-set sta-
tion advance functions of the RAZ radio receiver. The
CTM monitors the status of the remote radio
switches located on the steering wheel through a
hard wired circuit. The CTM then sends the proper
switch status messages to the radio receiver. The
electronic circuitry within the radio receiver responds
to the switch status messages it receives by adjusting
the radio settings as requested.
Refer to Electrical, Body Control/Central Timer
Module for more information on the high-line CTM.
Refer to Remote Radio Switch in Description and
Operation for more information on this component.
In addition, radio receivers connected to the CCD
data bus have several audio system functions that
can be diagnosed using a DRBIIItscan tool. Refer to
the proper Diagnostic Procedures manual for more
information on DRBIIIttesting of the audio systems.
DIAGNOSIS AND TESTING - AUDIO
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, REFER TO ELECTRICAL, RESTRAINTS
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, OR INSTRUMENT PANEL
COMPONENT DIAGNOSIS OR SERVICE. FAILURE
TO TAKE THE PROPER PRECAUTIONS COULD
RESULT IN ACCIDENTAL AIRBAG DEPLOYMENT
AND POSSIBLE PERSONAL INJURY.
Audio System Diagnosis
CONDITION POSSIBLE CAUSE CORRECTION
NO AUDIO 1. Fuse faulty. 1. Check radio fuses in junction block. Replace faulty
fuses, if required.
2. Radio connector faulty. 2. Check for loose or corroded radio connections. Repair,
if required.
3. Wiring faulty. 3. Check for battery voltage at radio connector. Repair
wiring, if required.
4. Ground faulty. 4. Check for continuity between radio chassis and a
known good ground. There should be continuity. Repair
ground, if required.
5. Radio faulty. 5. Refer to Radio in the Diagnosis and Testing section of
this group.
6. Speakers faulty. 6. Refer to Speaker in the Diagnosis and Testing section
of this group.
7. Amplifier faulty (if
equipped).7. Refer to Speaker in the Diagnosis and Testing section
of this group.
8A - 2 AUDIOBR/BE
AUDIO (Continued)

RADIO
DESCRIPTION
Available factory-installed radio receivers for this
model include an AM/FM/cassette (RAS sales code),
an AM/FM/CD/3-band graphic equalizer (RBR sales
code), or an AM/FM/CD/cassette/3-band graphic
equalizer (RAZ sales code). The factory-installed RAZ
sales code radio receivers can also communicate on
the Chrysler Collision Detection (CCD) data bus net-
work through a separate two-way wire harness con-
nector. All factory-installed receivers are stereo
Electronically Tuned Radios (ETR) and include an
electronic digital clock function.
These radio receivers can only be serviced by an
authorized radio repair station. See the latest War-
ranty Policies and Procedures manual for a current
listing of authorized radio repair stations.
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 battery current when the
ignition switch is in the Off position, including the
clock. The IOD fuse is removed to prevent battery
discharge during vehicle storage.
When removing or installing the IOD fuse, it is
important 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 and replaced.
Removing and replacing the IOD fuse again, with the
ignition switch in the Off position, will correct the
scrambled display condition.
The IOD fuse should be checked if the radio or
clock displays are inoperative. The IOD fuse is
located in the junction block. Refer to the fuse layout
label on the back of the instrument panel fuse access
panel for IOD fuse identification and location.
OPERATION
The radio receiver operates on fused battery cur-
rent that is available only when the ignition switch is
in the On or Accessory positions. The electronic digi-
tal clock function of the radio operates on fused bat-
tery current supplied through the IOD fuse,
regardless of the ignition switch position.
For more information on the features, setting pro-
cedures, and control functions for each of the avail-
able factory-installed radio receivers, see the owner's
manual in the vehicle glove box. For complete circuit
diagrams, refer to the appropriate wiring informa-
tion. The wiring information includes wiring dia-
grams, proper wire and connector repair procedures,
details of wire harness routing and retention, connec-
tor pin-out information and location views for the
various wire harness connectors, splices and grounds.
DIAGNOSIS AND TESTING - RADIO
If the vehicle is equipped with the optional remote
radio switches located on the steering wheel and the
problem being diagnosed is related to one of the
symptoms listed below, be certain to check the
remote radio switches and circuits. Refer to Audio,
Remote Radio Switch prior to attempting radio diag-
nosis or repair.
²Stations changing with no remote radio switch
input
²Radio memory presets not working properly
²Volume changes with no remote radio switch
input
²Remote radio switch buttons taking on other
functions
²CD player skipping tracks
²Remote radio switch inoperative.
For complete circuit diagrams, refer to the appro-
priate wiring information. The wiring information
includes wiring diagrams, proper wire and connector
repair procedures, details of wire harness routing
and retention, connector pin-out information and
location views for the various wire harness connec-
tors, splices and grounds.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, REFER TO ELECTRICAL, RESTRAINTS
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, OR INSTRUMENT PANEL
COMPONENT DIAGNOSIS OR SERVICE. FAILURE
TO TAKE THE PROPER PRECAUTIONS COULD
RESULT IN ACCIDENTAL AIRBAG DEPLOYMENT
AND POSSIBLE PERSONAL INJURY.
CAUTION: The speaker output of the radio receiver
is a ªfloating groundº system. Do not allow any
speaker lead to short to ground, as damage to the
radio receiver may result.
(1) Check the fused B(+) fuse in the junction block.
If OK, go to Step 2. If not OK, repair the shorted cir-
cuit or component as required and replace the faulty
fuse.
(2) Check for battery voltage at the fused B(+) fuse
in the junction block. If OK, go to Step 3. If not OK,
repair the open fused B(+) circuit to the Power Dis-
tribution Center (PDC) as required.
(3) Check the fused ignition switch output (acc/
run) fuse in the junction block. If OK, go to Step 4. If
not OK, repair the shorted circuit or component as
required and replace the faulty fuse(s).
(4) Turn the ignition switch to the On position.
Check for battery voltage at the fused ignition switch
output (acc/run) fuse in the junction block. If OK, go
to Step 5. If not OK, repair the open fused ignition
8A - 10 AUDIOBR/BE

Electrical, Body Control/Central Timer Module for
more information on this component.
Two rocker-type switches (Fig. 15) are mounted in
the sides of the rear (instrument panel side) steering
wheel trim cover. The switch on the left side is the
seek switch and has seek up, seek down, and preset
station advance functions. The switch on the right
side is the volume control switch and has volume up,
and volume down functions. The two switches are
retained in mounting holes located on each side of
the rear steering wheel trim cover by four latches
that are integral to the switches.
The remote radio switches share a common steer-
ing wheel wire harness with the vehicle speed control
switches. The steering wheel wire harness is con-
nected to the instrument panel wire harness through
the clockspring. Refer to Electrical, Clockspring for
more information on this component.
OPERATION
The remote radio switches are resistor multiplexed
units that are hard wired to the high-line or pre-
mium CTM through the clockspring. The CTM mon-
itors the status of the remote radio switches and
sends the proper switch status messages on the
Chrysler Collision Detection (CCD) data bus network
to the radio receiver. The electronic circuitry within
the radio is programmed to respond to these remote
radio switch status messages by adjusting the radio
settings as requested.
For diagnosis of the CTM or the CCD data bus, the
use of a DRBIIItscan tool and the proper DiagnosticProcedures manual 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. For complete circuit
diagrams, refer to the appropriate wiring informa-
tion. The wiring information includes wiring dia-
grams, proper wire and connector repair procedures,
details of wire harness routing and retention, connec-
tor pin-out information and location views for the
various wire harness connectors, splices and grounds.
DIAGNOSIS AND TESTING - REMOTE
SWITCHES
For complete circuit diagrams, refer to the appro-
priate wiring information. The wiring information
includes wiring diagrams, proper wire and connector
repair procedures, details of wire harness routing
and retention, connector pin-out information and
location views for the various wire harness connec-
tors, splices and grounds.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, REFER TO ELECTRICAL, RESTRAINTS
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, OR INSTRUMENT PANEL
COMPONENT DIAGNOSIS OR SERVICE. FAILURE
TO TAKE THE PROPER PRECAUTIONS COULD
RESULT IN ACCIDENTAL AIRBAG DEPLOYMENT
AND POSSIBLE PERSONAL INJURY.
(1) Remove the remote radio switch(es) (Fig. 16)
from the steering wheel.
Fig. 15 Remote Radio Switches
1 - PRESET SEEK
2-UP
3 - SEEK
4 - VOLUME
5 - DOWN
Fig. 16 Remote Radio Switches
1 - WHITE REAR SWITCH
2 - BLACK REAR SWITCH
BR/BEAUDIO 8A - 15
REMOTE SWITCHES (Continued)

(2) Use an ohmmeter to check the switch resis-
tances as shown in the Remote Radio Switch Test
chart. If the remote radio switch resistances check
OK, go to Step 3. If not OK, replace the faulty
switch.
REMOTE RADIO SWITCH TEST
SWITCH SWITCH POSITION RESISTANCE
Right
(White)Volume Up 7320 Ohms
Right
(White)Volume Down 1210 Ohms
Left
(Black)Seek Up 4530 Ohms
Left
(Black)Seek Down 2050 Ohms
Left
(Black)Pre-Set Station
Advance10 Ohms
(3) Check for continuity between the ground cir-
cuit cavity of the remote radio switch wire harness
connector and a good ground. There should be conti-
nuity. If OK, go to Step 4. If not OK, repair the open
ground circuit to ground as required.
(4) Disconnect the 18-way wire harness connector
from the Central Timer Module (CTM). Check for
continuity between the radio control mux circuit cav-
ity of the remote radio switch wire harness connector
and a good ground. There should be no continuity. If
OK, go to Step 5. If not OK, repair the shorted radio
control mux circuit as required.
(5) Check for continuity between the radio control
mux circuit cavities of the remote radio switch wire
harness connector and the 18-way CTM wire harness
connector. There should be continuity. If OK, refer to
the proper Diagnostic Procedures manual to test the
CTM and the Chrysler Collision Detection (CCD)
data bus. If not OK, repair the open radio control
mux circuit as required.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the driver side airbag module from the
steering wheel. Refer to Electrical, Restraints for the
procedures.
(3) Remove the speed control switch located on the
same side of the steering wheel as the remote radio
switch that is being serviced. Refer to Electrical,
Speed Control for the procedures.
(4) Disconnect the steering wheel wire harness
connector from the connector receptacle of the remote
radio switch (Fig. 17).(5) Disengage the four remote radio switch latches
that secure the switch to the inside of the mounting
hole in the steering wheel rear trim cover.
(6) From the outside of the steering wheel rear
trim cover, remove the remote radio switch from the
trim cover mounting hole.
INSTALLATION
(1) Position the remote radio switch to the mount-
ing hole on the outside of the steering wheel rear
trim cover. Be certain that the connector receptacle is
oriented toward the bottom of the switch and pointed
toward the center of the steering wheel.
(2) Press firmly and evenly on the remote radio
switch until each of the switch latches is fully
engaged in the mounting hole of the steering wheel
rear trim cover.
(3) Reconnect the steering wheel wire harness con-
nector to the connector receptacle of the remote radio
switch.
(4) Install the speed control switch onto the steer-
ing wheel. Refer to Electrical, Speed Control for the
procedures.
Fig. 17 Remote Radio Switches Remove/Install
1 - STEERING WHEEL
2 - REMOTE RADIO SWITCH
3 - SPEED CONTROL SWITCH
4 - SCREW (2)
5 - DRIVER SIDE AIRBAG MODULE
6 - SPEED CONTROL SWITCH
7 - REAR TRIM COVER
8 - SCREW (2)
8A - 16 AUDIOBR/BE
REMOTE SWITCHES (Continued)

Excessive IOD can be caused by:
²Electrical items left on.
²Faulty or improperly adjusted switches.
²Faulty or shorted electronic modules and compo-
nents.
²An internally shorted generator.
²Intermittent shorts in the wiring.
If the IOD is over thirty-five milliamperes, the
problem must be found and corrected before replac-
ing a battery. In most cases, the battery can becharged and returned to service after the excessive
IOD condition has been corrected.
(1) Verify that all electrical accessories are off.
Turn off all lamps, remove the ignition key, and close
all doors. If the vehicle is equipped with an illumi-
nated entry system or an electronically tuned radio,
allow the electronic timer function of these systems
to automatically shut off (time out). This may take
up to three minutes. See the Electronic Module Igni-
tion-Off Draw Table for more information.
ELECTRONIC MODULE IGNITION-OFF DRAW (IOD) TABLE
ModuleTime Out?
(If Yes, Interval And Wake-Up Input)IOD IOD After Time Out
Radio No 1 to 3 milliamperes N/A
Audio Power
AmplifierNo up to 1 milliampere N/A
Central Timer
Module (CTM)No4.75 milliamperes
(max.)N/A
Powertrain Control
Module (PCM)No 0.95 milliampere N/A
ElectroMechanical
Instrument Cluster
(EMIC)No 0.44 milliampere N/A
Combination Flasher No 0.08 milliampere N/A
(2) Determine that the underhood lamp is operat-
ing properly, then disconnect the lamp wire harness
connector or remove the lamp bulb.
(3) Disconnect the battery negative cable.
(4) Set an electronic digital multi-meter to its
highest amperage scale. Connect the multi-meter
between the disconnected battery negative cable ter-
minal clamp and the battery negative terminal post.
Make sure that the doors remain closed so that the
illuminated entry system is not activated. The multi-
meter amperage reading may remain high for up to
three minutes, or may not give any reading at all
while set in the highest amperage scale, depending
upon the electrical equipment in the vehicle. The
multi-meter leads must be securely clamped to the
battery negative cable terminal clamp and the bat-
tery negative terminal post. If continuity between the
battery negative terminal post and the negative cable
terminal clamp is lost during any part of the IOD
test, the electronic timer function will be activated
and all of the tests will have to be repeated.
(5) After about three minutes, the high-amperage
IOD reading on the multi-meter should become very
low or nonexistent, depending upon the electrical
equipment in the vehicle. If the amperage reading
remains high, remove and replace each fuse or circuit
breaker in the Power Distribution Center (PDC) andthen in the Junction Block (JB), one at a time until
the amperage reading becomes very low, or nonexist-
ent. Refer to the appropriate wiring information in
this service manual for complete PDC and JB fuse,
circuit breaker, and circuit identification. This will
isolate each circuit and identify the circuit that is the
source of the high-amperage IOD. If the amperage
reading remains high after removing and replacing
each fuse and circuit breaker, disconnect the wire
harness from the generator. If the amperage reading
now becomes very low or nonexistent, refer to Charg-
ing System for the proper charging system diagnosis
and testing procedures. After the high-amperage IOD
has been corrected, switch the multi-meter to pro-
gressively lower amperage scales and, if necessary,
repeat the fuse and circuit breaker remove-and-re-
place process to identify and correct all sources of
excessive IOD. It is now safe to select the lowest mil-
liampere scale of the multi-meter to check the low-
amperage IOD.
CAUTION: Do not open any doors, or turn on any
electrical accessories with the lowest milliampere
scale selected, or the multi-meter may be damaged.
(6) Observe the multi-meter reading. The low-am-
perage IOD should not exceed thirty-five milliam-
peres (0.035 ampere). If the current draw exceeds
8F - 14 BATTERY SYSTEMBR/BE
BATTERY (Continued)