1998 DODGE RAM 1500 table of contents

COOLING
TABLE OF CONTENTS
page page
COOLING
DESCRIPTION
DESCRIPTION - COOLING SYSTEM FLOW
3.7L/4.7L/5.7L ENGINE..................1
DESCRIPTION - COOLING SYSTEM FLOW -
5.9L DIESEL..........................3
DESCRIPTION - HOSE CLAMPS...........3
OPERATION
OPERATION - COOLING SYSTEM.........5
OPERATION - HOSE CLAMPS............5
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTINGÐON-BOARD
DIAGNOSTICS (OBD)...................5
DIAGNOSIS AND TESTING - COOLING
SYSTEM - TESTING FOR LEAKS..........5
DIAGNOSIS AND TESTING - COOLING
SYSTEM DIESEL ENGINE................7
DIAGNOSIS AND TESTING - PRELIMINARY
CHECKS............................10
STANDARD PROCEDURE
STANDARD PROCEDURE - COOLANT
LEVEL CHECK........................17STANDARD PROCEDURE - COOLING
SYSTEM CLEANING/REVERSE FLUSHING . . 17
STANDARD PROCEDURE - DRAINING
COOLING SYSTEM - ALL GAS ENGINES . . . 17
STANDARD PROCEDURE - REFILLING
COOLING SYSTEM - ALL GAS ENGINES . . . 18
STANDARD PROCEDURE - DRAINING
COOLING SYSTEM 5.9L DIESEL ENGINE . . . 18
STANDARD PROCEDURE - REFILLING
COOLING SYSTEM 5.9L DIESEL ENGINE . . . 19
STANDARD PROCEDURE - ADDING
ADDITIONAL COOLANT.................19
SPECIFICATIONS
TORQUE............................19
SPECIFICATIONS -....................20
SPECIAL TOOLS
COOLING...........................20
ACCESSORY DRIVE......................21
ENGINE...............................30
TRANSMISSION.........................67
COOLING
DESCRIPTION
DESCRIPTION - COOLING SYSTEM FLOW
3.7L/4.7L/5.7L ENGINE
The cooling system regulates engine operating tem-
perature. It allows the engine to reach normal oper-
ating temperature as quickly as possible. It also
maintains normal operating temperature and pre-
vents overheating.The cooling system provides a means of heating
the passenger compartment and cooling the auto-
matic transmission fluid (if equipped). The cooling
system is pressurized and uses a centrifugal water
pump to circulate coolant through the system. The
coolant recovery/reserve system utilizes an ambient
overflow bottle (Fig. 2).
An optional factory installed maximum duty cool-
ing package is available on most models. This pack-
age will provide additional cooling capacity for
vehicles used under extreme conditions such as
trailer towing in high ambient temperatures (Fig. 1).
DRCOOLING 7 - 1

ACCESSORY DRIVE
TABLE OF CONTENTS
page page
BELT TENSIONER - 3.7L / 4.7L
DESCRIPTION.........................21
OPERATION...........................21
REMOVAL.............................21
INSTALLATION.........................22
BELT TENSIONER-5.7L
DESCRIPTION.........................22
OPERATION...........................22
REMOVAL.............................22
INSTALLATION.........................23
BELT TENSIONER - 5.9L DIESEL
DESCRIPTION.........................23
OPERATION...........................23REMOVAL.............................23
INSTALLATION.........................24
DRIVE BELT - 3.7L / 4.7L
DIAGNOSIS AND TESTING - ACCESSORY
DRIVE BELT.........................24
REMOVAL.............................26
INSTALLATION.........................26
DRIVE BELT - 5.9L DIESEL
DIAGNOSIS AND TESTINGÐACCESSORY
DRIVE BELT.........................27
REMOVAL.............................29
INSTALLATION.........................29
BELT TENSIONER - 3.7L / 4.7L
DESCRIPTION
Correct drive belt tension is required to ensure
optimum performance of the belt driven engine acces-
sories. If specified tension is not maintained, belt
slippage may cause; engine overheating, lack of
power steering assist, loss of air conditioning capac-
ity, reduced generator output rate, and greatly
reduced belt life.
It is not necessary to adjust belt tension on the
3.7L or 4.7L engine. These engines are equipped with
an automatic belt tensioner (Fig. 1). The tensioner
maintains correct belt tension at all times. Due to
use of this belt tensioner, do not attempt to use a belt
tension gauge on 3.7L or 4.7L engines.
OPERATION
The automatic belt tensioner maintains belt ten-
sion by using internal spring pressure, a pivoting
arm and pulley to press against the drive belt.
REMOVAL
On 3.7L and 4.7L engines, the tensioner is
equipped with an indexing tang on back of ten-
sioner and an indexing stop on tensioner hous-
ing. If a new belt is being installed, tang must
be within approximately 24 mm (.94 inches) of
indexing stop. Belt is considered new if it has
been used 15 minutes or less.
If the above specification cannot be met, check for:²The wrong belt being installed (incorrect length/
width)
²Worn bearings on an engine accessory (A/C com-
pressor, power steering pump, water pump, idler pul-
ley or generator)
²A pulley on an engine accessory being loose
²Misalignment of an engine accessory
²Belt incorrectly routed.
NOTE: A used belt should be replaced if tensioner
indexing arrow has moved to the minimum tension
indicator. Tensioner travel stops at this point.
Fig. 1 AUTOMATIC BELT TENSIONER
1 - AUTOMATIC TENSIONER ASSEMBLY
DRACCESSORY DRIVE 7 - 21

ENGINE
TABLE OF CONTENTS
page page
COOLANT
DESCRIPTION
DESCRIPTION - ENGINE COOLANT.......31
DESCRIPTION - HOAT COOLANT.........32
OPERATION...........................33
COOLANT RECOVERY CONTAINER- GAS
ENGINES
DESCRIPTION.........................33
OPERATION...........................33
REMOVAL.............................33
INSTALLATION.........................33
RADIATOR FAN - GAS ENGINES
REMOVAL.............................33
CLEANING............................34
INSPECTION..........................34
INSTALLATION.........................34
RADIATOR FAN - 5.9L DIESEL
REMOVAL.............................35
CLEANING............................35
INSPECTION..........................35
INSTALLATION.........................36
ENGINE BLOCK HEATER
DESCRIPTION.........................36
OPERATION...........................36
DIAGNOSIS AND TESTING - ENGINE BLOCK
HEATER ............................36
REMOVAL.............................37
INSTALLATION.........................37
ENGINE BLOCK HEATER - 5.9L DIESEL
DESCRIPTION.........................37
OPERATION...........................38
REMOVAL.............................38
INSTALLATION.........................38
ENGINE COOLANT TEMPERATURE SENSOR
DESCRIPTION.........................38
OPERATION...........................38
REMOVAL.............................39
INSTALLATION.........................41
ENGINE COOLANT THERMOSTAT- 5.7L
DESCRIPTION.........................41
OPERATION...........................41
DIAGNOSIS AND TESTINGÐTHERMOSTAT . . . 42
REMOVAL.............................42
INSTALLATION.........................43
ENGINE COOLANT THERMOSTAT - 3.7L/4.7L
DESCRIPTION.........................44
OPERATION...........................44
DIAGNOSIS AND TESTINGÐTHERMOSTAT . . . 44
REMOVAL.............................45INSTALLATION.........................45
ENGINE COOLANT THERMOSTAT - 5.9L
DIESEL
DESCRIPTION.........................46
OPERATION...........................46
DIAGNOSIS AND TESTING - THERMOSTAT . . . 47
REMOVAL.............................47
INSTALLATION.........................47
ENGINE COOLANT THERMOSTAT - 8.0L
DESCRIPTION.........................48
OPERATION...........................48
DIAGNOSIS AND TESTING - THERMOSTAT . . . 48
REMOVAL.............................49
INSTALLATION.........................49
FAN DRIVE VISCOUS CLUTCH-GAS ENGINES
DESCRIPTION.........................50
OPERATION...........................50
DIAGNOSIS AND TESTING - VISCOUS FAN
DRIVE..............................50
FAN DRIVE VISCOUS CLUTCH - 5.9L DIESEL
DESCRIPTION.........................52
OPERATION...........................52
DIAGNOSIS AND TESTING -
ELECTRONICALLY CONTROLLED VISCOUS
FAN DRIVE..........................52
RADIATOR-3.7L/4.7L/5.7L
DESCRIPTION.........................54
OPERATION...........................54
DIAGNOSIS AND TESTING - RADIATOR
COOLANT FLOW......................54
REMOVAL.............................54
CLEANING............................55
INSPECTION..........................55
INSTALLATION.........................55
RADIATOR - 5.9L DIESEL
DESCRIPTION.........................56
OPERATION...........................56
DIAGNOSIS AND TESTING - RADIATOR
COOLANT FLOW......................56
REMOVAL.............................56
CLEANING............................56
INSPECTION..........................56
INSTALLATION.........................57
RADIATOR PRESSURE CAP
DESCRIPTION.........................57
OPERATION...........................58
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - RADIATOR
CAP-TO-FILLER NECK SEAL.............58
7 - 30 ENGINEDR

TRANSMISSION
TABLE OF CONTENTS
page page
TRANS COOLER
DESCRIPTION.........................67
OPERATION...........................67
REMOVAL.............................68
INSTALLATION.........................68
TRANS COOLER - 5.9L DIESEL
DESCRIPTION.........................68
OPERATION...........................69REMOVAL
REMOVAL - AIR TO OIL COOLER.........69
REMOVAL - WATER TO OIL COOLER......69
DISASSEMBLY - 5.9L DIESEL ONLY.........70
ASSEMBLY - 5.9L DIESEL ONLY...........70
INSTALLATION
INSTALLATION - AIR TO OIL COOLER.....70
INSTALLATION - WATER-TO-AIR COOLER . . 70
TRANS COOLER
DESCRIPTION
An air-to-oil transmission oil cooler is standard on
all engine packages. The transmission oil cooler is
mounted to the front of the radiator above the power
steering cooler (Fig. 1) and (Fig. 2)
OPERATION
Transmission oil is routed through the cooler
where heat is removed from the transmission oil
before returning to the transmission.
Fig. 1 Cooling Module - 3.7L/4.7L/5.7L
1 - TRANS OIL COOLER
2 - LOCATING TABS
3 - POWER STEERING OIL COOLER
4 - POWER STEERING OIL COOLER MOUNTING BOLT
5 - TRANS OIL COOLER OUTLET
6 - TRANS OIL COOLER INLET
7 - COOLER LINE CLIP
8 - COOLER LINE CLIP
9 - MOUNTING BOLT
10 - RADIATOR
Fig. 2 COOLING MODULE - 5.9L GAS
1 - TRANS OIL COOLER BYPASS (5.9L only)
2 - OIL COOLER THERMOSTATIC BYPASS VALVE (5.9L only)
3 -TRANS OIL COOLER
4 - OIL COOLER MOUNTING BOLT (4)
5 - POWER STEERING COOLER
6 - POWER STEERING COOLER MOUNTING BOLT(2)
7 - TRANS OIL COOLER OUTLET
8 - TRANS OIL COOLER INLET
9 - COOLER LINE CLIP
10 - COOLER LINE CLIP
11 - RADIATOR
DRTRANSMISSION 7 - 67

AUDIO/VIDEO
TABLE OF CONTENTS
page page
AUDIO
DESCRIPTION..........................1
OPERATION............................1
DIAGNOSIS AND TESTING - AUDIO..........2
AMPLIFIER
DESCRIPTION..........................3
OPERATION............................3
REMOVAL.............................3
INSTALLATION..........................4
ANTENNA BODY & CABLE
DESCRIPTION..........................4
OPERATION............................4
DIAGNOSIS AND TESTING - ANTENNA BODY
AND CABLE..........................4
REMOVAL.............................6
INSTALLATION..........................6
ANTENNA - NAVIGATION
REMOVAL.............................6
INSTALLATION..........................6
INSTRUMENT PANEL ANTENNA CABLE
REMOVAL.............................7
INSTALLATION..........................7
RADIO
DESCRIPTION..........................8OPERATION............................8
REMOVAL.............................8
INSTALLATION..........................8
RADIO NOISE SUPPRESSION GROUND STRAP
DESCRIPTION..........................9
OPERATION............................9
REMOVAL.............................9
INSTALLATION.........................10
REMOTE SWITCHES
DESCRIPTION.........................10
OPERATION...........................11
DIAGNOSIS AND TESTING - REMOTE
SWITCHES..........................11
REMOVAL.............................12
INSTALLATION.........................12
SPEAKER
DESCRIPTION.........................13
OPERATION...........................13
DIAGNOSIS AND TESTING - SPEAKER......13
REMOVAL.............................14
INSTALLATION.........................15
AUDIO
DESCRIPTION
Several combinations of radio receivers and
speaker systems are offered. The audio 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 positions.
A optional navigation radio (RB4) is available on
this vehicle. With this system, the operator has the
option of choosing a street address, point of interest,
trip itinerary and other features outlined in the oper-
ator's manual.
The audio system includes the following compo-
nents:
²Antenna
²Power amplifier (with premium speaker system
only)
²Radio noise suppression components
²Radio receiver
²Remote radio switches (if equipped)
²SpeakersCertain functions and features of the audio system
rely upon resources shared with other electronic
modules in the vehicle over the Programmable Com-
munication Interface (PCI) bus network. The data
bus network allows the sharing of sensor informa-
tion. For diagnosis of these electronic modules or of
the data bus network, the use of a DRB IIItscan tool
and the proper Diagnostic Procedures manual are
recommended.
OPERATION
The audio system components are designed to pro-
vide audio entertainment and information through
the reception, tuning and amplification of locally
broadcast radio signals in both the Amplitude Modu-
lating (AM) and Frequency Modulating (FM) com-
mercial frequency ranges.
The audio system components operate on battery
current received through a fuse in the Integrated
Power Module (IPM) on a fused ignition switch out-
put (run-acc) circuit so that the system will only
operate when the ignition switch is in the Run or
Accessory positions.
DRAUDIO/VIDEO 8A - 1

CHIME/BUZZER
TABLE OF CONTENTS
page page
CHIME WARNING SYSTEM
DESCRIPTION..........................1
OPERATION............................1DIAGNOSIS AND TESTING - CHIME
WARNING SYSTEM.....................3
CHIME WARNING SYSTEM
DESCRIPTION
A chime warning system is standard factory-in-
stalled equipment on this model. The chime warning
system uses a single chime tone generator that is
integral to the instrument cluster to provide an audi-
ble indication of various vehicle conditions that may
require the attention of the vehicle operator. The
chime warning system includes the following major
components, which are described in further detail
elsewhere in this service information:
²Door Ajar Switch- A door ajar switch is inte-
gral to each door latch. This switch provides an input
to the chime warning system indicating whether the
front doors are open or closed.
²Ignition Switch- A key-in ignition switch is
integral to the ignition switch. The key-in ignition
switch provides an input to the chime warning sys-
tem indicating whether a key is present in the igni-
tion lock cylinder.
²Instrument Cluster- The instrument cluster
contains an integral chime tone generator, integrated
circuitry, a central processing unit and the program-
ming to provide all of the proper chime warning sys-
tem features based upon the monitored inputs. The
instrument cluster circuitry monitors hard-wired
switch inputs, as well as message inputs received
from other vehicle electronic modules on the Pro-
grammable Communications Interface (PCI) data bus
network.
²Headlamp Switch- The headlamp switch pro-
vides an input to the chime warning system indicat-
ing when the exterior lamps are turned On or Off.
²Seat Belt Switch- A seat belt switch is inte-
gral to the driver seat belt buckle-half unit. The seat
belt switch provides an input to the chime warning
system indicating whether the driver seat belt is fas-
tened.
Hard wired circuitry connects many of the chime
warning system components to each other through
the electrical system of the vehicle. These hard wired
circuits are integral to several wire harnesses, which
are routed throughout the vehicle and retained bymany different methods. Refer to the appropriate
wiring information.
The instrument cluster chime warning system cir-
cuitry and the integral chime tone generator cannot
be adjusted or repaired. If the instrument cluster or
the chime tone generator are damaged or faulty, the
instrument cluster must be replaced.
OPERATION
The chime warning system is designed to provide
an audible output as an indication of various condi-
tions that may require the attention or awareness of
the vehicle operator. The chime warning system com-
ponents operate on battery voltage received through
the Ignition-Off Draw (IOD) fuse in the Power Distri-
bution Center (PDC) so that the system may operate
regardless of the ignition switch position.
The chime warning system provides an audible
warning to the vehicle operator under the following
conditions:
²Air Bag Warning- The instrument cluster
chime tone generator will generate a single chime
tone when the airbag indicator is illuminated for an
airbag system fault condition. The instrument cluster
uses airbag indicator lamp-on and lamp-off message
inputs received from the Airbag Control Module
(ACM) over the Programmable Communications
Interface (PCI) data bus indicating that the airbag
indicator should be illuminated for an airbag system
fault condition.
²Door Ajar Warning- The instrument cluster
chime tone generator will generate a single chimes to
announce that the hard wired inputs from the door
ajar switches and the ignition switch as well as an
engine speed message input received from the PCM
over the PCI data bus indicate that a driver or pas-
senger door is opened with the ignition switch in the
On position and vehicle speed present.
²Engine Coolant Temperature High Warning
(Diesel Engine Only)- The instrument cluster
chime tone generator will generate a single chime
tone when the check gauges indicator is illuminated
for a high or critical engine coolant temperature con-
dition. The instrument cluster uses engine coolant
temperature message inputs received from the diesel
DRCHIME/BUZZER 8B - 1

ELECTRONIC CONTROL MODULES
TABLE OF CONTENTS
page page
COMMUNICATION
DESCRIPTION..........................1
OPERATION............................2
CONTROLLER ANTILOCK BRAKE
DESCRIPTION..........................3
OPERATION............................3
REMOVAL.............................3
INSTALLATION..........................3
DATA LINK CONNECTOR
DESCRIPTION - DATA LINK CONNECTOR.....3
OPERATION - DATA LINK CONNECTOR......3
ENGINE CONTROL MODULE
DESCRIPTION - ECM.....................3
OPERATION - ECM......................3
REMOVAL.............................4
INSTALLATION..........................4
FRONT CONTROL MODULE
DESCRIPTION..........................5
OPERATION............................5
DIAGNOSIS AND TESTING - FRONT
CONTROL MODULE....................5
REMOVAL.............................5
INSTALLATION..........................5
HEATED SEAT MODULE
DESCRIPTION..........................6
OPERATION............................6
DIAGNOSIS AND TESTING - HEATED SEAT
MODULE.............................6
REMOVAL.............................7
INSTALLATION..........................7
POWERTRAIN CONTROL MODULE
DESCRIPTION
DESCRIPTION - PCM...................7DESCRIPTION - MODES OF OPERATION....7
DESCRIPTION - 5 VOLT SUPPLIES.......10
DESCRIPTION - IGNITION CIRCUIT SENSE . 10
DESCRIPTION - POWER GROUNDS......10
DESCRIPTION - SENSOR RETURN.......10
OPERATION
OPERATION - PCM....................10
OPERATION - 5 VOLT SUPPLIES.........11
OPERATION - IGNITION CIRCUIT SENSE . . . 11
REMOVAL.............................12
INSTALLATION.........................12
SENTRY KEY IMMOBILIZER MODULE
DESCRIPTION.........................13
OPERATION...........................13
STANDARD PROCEDURE - PCM/SKIM
PROGRAMMING......................14
REMOVAL.............................15
INSTALLATION.........................15
TRANSFER CASE CONTROL MODULE
DESCRIPTION.........................16
OPERATION...........................16
TRANSMISSION CONTROL MODULE
DESCRIPTION.........................20
OPERATION...........................20
STANDARD PROCEDURE
STANDARD PROCEDURE - TCM QUICK
LEARN..............................23
STANDARD PROCEDURE - DRIVE LEARN . . 23
COMMUNICATION
DESCRIPTION
The DaimlerChrysler Programmable Communica-
tion Interface (PCI) data bus system is a single wire
multiplex system used for vehicle communications on
many DaimlerChrysler Corporation vehicles. Multi-
plexing is a system that enables the transmission of
several messages over a single channel or circuit. All
DaimlerChrysler vehicles use this principle for com-
munication between various microprocessor-based
electronic control modules. The PCI data bus exceeds
the Society of Automotive Engineers (SAE) J1850
Standard for Class B Multiplexing.Many of the electronic control modules in a vehicle
require information from the same sensing device. In
the past, if information from one sensing device was
required by several controllers, a wire from each con-
troller needed to be connected in parallel to that sen-
sor. In addition, each controller utilizing analog
sensors required an Analog/Digital (A/D) converter in
order to9read9these sensor inputs. Multiplexing
reduces wire harness complexity, sensor current
loads and controller hardware because each sensing
device is connected to only one controller, which
reads and distributes the sensor information to the
other controllers over the data bus. Also, because
each controller on the data bus can access the con-
troller sensor inputs to every other controller on the
DRELECTRONIC CONTROL MODULES 8E - 1

ENGINE SYSTEMS
TABLE OF CONTENTS
page page
BATTERY SYSTEM......................... 1
CHARGING.............................. 19STARTING............................... 26
BATTERY SYSTEM
TABLE OF CONTENTS
page page
BATTERY SYSTEM
DESCRIPTION..........................1
OPERATION............................2
DIAGNOSIS AND TESTING - BATTERY
SYSTEM.............................2
CLEANING.............................5
INSPECTION...........................5
SPECIFICATIONS........................6
SPECIAL TOOLS
BATTERY SYSTEM SPECIAL TOOLS.......7
BATTERY
DESCRIPTION..........................7
DIAGNOSIS AND TESTING - BATTERY.......7
STANDARD PROCEDURE
STANDARD PROCEDURE - BATTERY
CHARGING...........................8
STANDARD PROCEDURE - BUILT-IN
INDICATOR TEST.....................10
STANDARD PROCEDURE - OPEN-CIRCUIT
VOLTAGE TEST.......................10
STANDARD PROCEDURE - IGNITION-OFF
DRAW TEST.........................11STANDARD PROCEDURE - USING MICRO
420 BATTERY TESTER.................12
REMOVAL.............................13
INSTALLATION.........................14
BATTERY HOLDDOWN
DESCRIPTION.........................14
OPERATION...........................14
REMOVAL.............................14
INSTALLATION.........................14
BATTERY CABLES
DESCRIPTION.........................14
OPERATION...........................15
DIAGNOSIS AND TESTING - BATTERY
CABLES............................15
REMOVAL.............................16
INSTALLATION.........................17
BATTERY TRAY
DESCRIPTION.........................17
OPERATION...........................17
REMOVAL.............................17
INSTALLATION.........................18
BATTERY SYSTEM
DESCRIPTION
A single 12-volt battery is standard factory-in-
stalled equipment on gasoline engine equipped mod-
els. Diesel engine equipped vehicles utilize two
12-volt batteries connected in parallel. All of the com-
ponents of the battery system are located within the
engine compartment of the vehicle. The battery sys-
tem for this vehicle, covers the following related com-
ponents, which are covered in further detail later in
this section of the service manual:²Battery- The storage battery provides a reli-
able means of storing a renewable source of electrical
energy within the vehicle.
²Battery Cables- The battery cables connect
the battery terminal posts to the vehicle electrical
system.
²Battery Holddown- The battery holddown
hardware secures the battery in the battery tray in
the engine compartment.
²Battery Tray- The battery tray provides a
secure mounting location in the vehicle for the bat-
tery and an anchor point for the battery holddown
hardware.
DRENGINE SYSTEMS 8F - 1