1998 DODGE RAM 1500 module

HORN
TABLE OF CONTENTS
page page
HORN SYSTEM
DESCRIPTION..........................1
OPERATION............................1
DIAGNOSIS AND TESTING - HORN SYSTEM . . . 1
HORN
DIAGNOSIS AND TESTING - HORN..........1REMOVAL.............................2
INSTALLATION..........................2
HORN SWITCH
DESCRIPTION..........................2
DIAGNOSIS AND TESTING - HORN SWITCH . . . 2
HORN SYSTEM
DESCRIPTION
The dual-note horn system features dual electro-
magnetic horn units. The horn system includes the
following major components:
²Horn- The two horns are located on the left
side of the engine compartment below the Integrated
Power Module (IPM).
²Horn Switch- The horn switch is molded into
the driver airbag trim cover.
OPERATION
The horn system operates on battery current
received through a fuse in the Integrated Power
Module (IPM). The horn system circuit is designed so
that the system will remain operational, regardless
of the ignition switch position.
DIAGNOSIS AND TESTING - HORN SYSTEM
The most reliable, efficient, and accurate
means to diagnose the horn system requires the
use of a DRBIIItscan tool and the proper Diag-
nostic Procedures manual.
Refer to the appropriate wiring information.
In most cases, any problem involving continually
sounding horns can be quickly alleviated by removing
the horn fuse from the Integrated Power Module
(IPM).
WARNING: DISABLE THE AIRBAG SYSTEM
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, SEAT BELT TENSIONER, SIDE
AIRBAG, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
HORN
DIAGNOSIS AND TESTING - HORN
The most reliable, efficient, and accurate
means to diagnose the horn system requires the
use of a DRBIIItscan tool and the proper Diag-
nostic Procedures manual. The DRBIIItscan
tool can provide confirmation that the PCI data
bus is functional, that all of the electronic mod-
ules are sending and receiving the proper mes-
sages on the PCI data bus, and that the horns
are being sent the proper hard wired outputs
for them to perform their functions.
Refer to the appropriate 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 connectors, splices and grounds.
WARNING: DISABLE THE AIRBAG SYSTEM
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, SEAT BELT TENSIONER, SIDE
AIRBAG, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
DRHORN 8H - 1

IGNITION CONTROL
TABLE OF CONTENTS
page page
IGNITION CONTROL
DESCRIPTION..........................1
SPECIFICATIONS
SPECIFICATIONS - TORQUE - IGNITION....3
ENGINE FIRING ORDER - 3.7L V-6.........4
ENGINE FIRING ORDER ± 4.7L V-8........4
FIRING ORDER / CABLE ROUTING ± 5.7L
V-8 ENGINE...........................4
SPARK PLUG CABLE RESISTANCE........4
SPARK PLUGS........................4
IGNITION COIL RESISTANCE - 3.7L V-6.....5
IGNITION COIL RESISTANCE - 4.7L V-8.....5
IGNITION COIL RESISTANCE - 5.7L V-8.....5
IGNITION TIMING......................5
AUTOMATIC SHUT DOWN RELAY
DESCRIPTION - PCM OUTPUT.............5
OPERATION
OPERATION - PCM OUTPUT.............5
OPERATION - ASD SENSE - PCM INPUT....5
DIAGNOSIS AND TESTING - ASD AND FUEL
PUMP RELAYS........................5
REMOVAL.............................6
INSTALLATION..........................6
CAMSHAFT POSITION SENSOR
DESCRIPTION..........................7
OPERATION............................7
REMOVAL.............................9
INSTALLATION.........................10IGNITION COIL
DESCRIPTION.........................11
OPERATION...........................12
REMOVAL.............................13
INSTALLATION.........................14
KNOCK SENSOR
DESCRIPTION.........................14
OPERATION...........................14
REMOVAL.............................15
INSTALLATION.........................15
SPARK PLUG
DESCRIPTION.........................17
DIAGNOSIS AND TESTING - SPARK PLUG
CONDITIONS.........................17
REMOVAL.............................19
CLEANING
CLEANING AND ADJUSTMENT...........20
INSTALLATION.........................20
IGNITION COIL CAPACITOR
DESCRIPTION.........................21
OPERATION...........................21
REMOVAL.............................21
INSTALLATION.........................21
SPARK PLUG CABLE
DESCRIPTION.........................21
OPERATION...........................21
REMOVAL.............................22
INSTALLATION.........................22
IGNITION CONTROL
DESCRIPTION
The ignition system is controlled by the Powertrain
Control Module (PCM) on all engines.
3.7L V-6 ENGINE
The 3.7L V-6 engine uses a separate ignition coil
for each cylinder. The one-piece coil bolts directly to
the cylinder head. Rubber boots seal the secondary
terminal ends of the coils to the top of all 6 spark
plugs. A separate electrical connector is used for each
coil.
Because of coil design, spark plug cables (second-
ary cables) are not used. A distributor is not used
with the 3.7L engine.
Two knock sensors (one for each cylinder bank) are
used to help control spark knock.The Auto Shutdown (ASD) relay provides battery
voltage to each ignition coil.
The ignition system consists of:
²6 Spark Plugs
²6 Separate Ignition Coils
²2 Knock Sensors
²Powertrain Control Module (PCM)
²Also to be considered part of the ignition system
are certain inputs from the Crankshaft Position,
Camshaft Position, Throttle Position, 2 knock and
MAP Sensors
4.7L V-8 ENGINE
The 4.7L V-8 engine uses a separate ignition coil
for each cylinder. The one-piece coil bolts directly to
the cylinder head. Rubber boots seal the secondary
terminal ends of the coils to the top of all 8 spark
plugs. A separate electrical connector is used for each
coil.
DRIGNITION CONTROL 8I - 1

Because of coil design, spark plug cables (second-
ary cables) are not used. A distributor is not used
with the 4.7L engine.
Two knock sensors (one for each cylinder bank) are
used to help control spark knock.
The Auto Shutdown (ASD) relay provides battery
voltage to each ignition coil.
The ignition system consists of:
²8 Spark Plugs
²8 Separate Ignition Coils
²2 Knock Sensors
²Powertrain Control Module (PCM)
²Also to be considered part of the ignition system
are certain inputs from the Crankshaft Position,
Camshaft Position, Throttle Position, 2 knock and
MAP Sensors
5.7L V-8 ENGINE
For additional information, also refer to Igni-
tion Coil Description and Operation.
The 5.7L V-8 engine is equipped with 16 spark
plugs. Two plugs are used for each cylinder. The 5.7L
is also equipped with 8 separate and independent
ignition coils. The one-piece coil bolts directly to the
cylinder head cover and attaches the coils secondary
output terminal directly to a spark plug using a rub-
ber boot seal. Each coil is also equipped with a sec-
ond output terminal. This second terminal connects a
conventional spark plug cable directly to a spark
plug on the opposite cylinder bank. A separate pri-
mary electrical connector is used for each coil.
Eight conventional spark plug cables are used with
the 5.7L. These cables connect a coil on one cylinder
bank, directly to a spark plug on the opposite cylin-
der bank. The cables are placed and routed in a spe-
cial plastic loom to keep them separated. This loom is
clipped to the intake manifold. To prevent a miss-
match of cables, a corresponding spark plug / coil
number is displayed on each plug cable: 1/6, 2/3, 4/7
and 5/8. These numbers can also be found on the top
of the intake manifold to the right of the throttle
body (Fig. 1).Two knock sensors (one for each cylinder bank) are
used to help control spark knock.
The 5.7L engine will not use a conventional distrib-
utor.
The ignition system consists of:
²16 Spark Plugs (2 per cylinder)
²8 Separate, Dual-Secondary Output, Ignition
Coils
²2 Knock Sensors
²8 Secondary Ignition Cables
²Powertrain Control Module (PCM)
²Also to be considered part of the ignition system
are certain inputs from the Crankshaft Position,
Camshaft Position, Throttle Position, 2 knock and
MAP Sensors
Fig. 1 FIRING ORDER / CABLE ROUTING - 5.7L V-8
ENGINE
1 - TOP OF INTAKE MANIFOLD
2 - CYLINDER FIRING ORDER (IGNITION COIL NUMBER)
3 - CORRESPONDING SPARK PLUG NUMBER
8I - 2 IGNITION CONTROLDR
IGNITION CONTROL (Continued)

IGNITION COIL RESISTANCE - 3.7L V-6
PRIMARY RESISTANCE
21-27ÉC (70-80ÉF)SECONDARY
RESISTANCE 21-27ÉC
(70-80ÉF)
0.6 - 0.9 Ohms 6,000 - 9,000 Ohms
IGNITION COIL RESISTANCE - 4.7L V-8
PRIMARY
RESISTANCE 21-27ÉC
(70-80ÉF)SECONDARY
RESISTANCE 21-27ÉC
(70-80ÉF)
0.6 - 0.9 Ohms 6,000 - 9,000 Ohms
IGNITION COIL RESISTANCE - 5.7L V-8
PRIMARY RESISTANCE @ 21-27ÉC (70-80ÉF)
0.558 - 0.682 Ohms
(Plus or Minus 10% @ 70-80É F)
IGNITION TIMING
Ignition timing is not adjustable on any engine.
AUTOMATIC SHUT DOWN
RELAY
DESCRIPTION - PCM OUTPUT
The 5±pin, 12±volt, Automatic Shutdown (ASD)
relay is located in the Power Distribution Center
(PDC). Refer to label on PDC cover for relay location.
OPERATION
OPERATION - PCM OUTPUT
The ASD relay supplies battery voltage (12+ volts)
to the fuel injectors and ignition coil(s). With certain
emissions packages it also supplies 12±volts to the
oxygen sensor heating elements.
The ground circuit for the coil within the ASD
relay is controlled by the Powertrain Control Module
(PCM). The PCM operates the ASD relay by switch-
ing its ground circuit on and off.
The ASD relay will be shut±down, meaning the
12±volt power supply to the ASD relay will be de-ac-
tivated by the PCM if:
²the ignition key is left in the ON position. This
is if the engine has not been running for approxi-
mately 1.8 seconds.
²there is a crankshaft position sensor signal to
the PCM that is lower than pre-determined values.
OPERATION - ASD SENSE - PCM INPUT
A 12 volt signal at this input indicates to the PCM
that the ASD has been activated. The relay is used to
connect the oxygen sensor heater element, ignition
coil and fuel injectors to 12 volt + power supply.
This input is used only to sense that the ASD relay
is energized. If the Powertrain Control Module
(PCM) does not see 12 volts at this input when the
ASD should be activated, it will set a Diagnostic
Trouble Code (DTC).
DIAGNOSIS AND TESTING - ASD AND FUEL
PUMP RELAYS
The following description of operation and
tests apply only to the Automatic Shutdown
(ASD) and fuel pump relays. The terminals on the
bottom of each relay are numbered. Two different
types of relays may be used, (Fig. 3) or (Fig. 4).
²Terminal number 30 is connected to battery volt-
age. For both the ASD and fuel pump relays, termi-
nal 30 is connected to battery voltage at all times.
²The PCM grounds the coil side of the relay
through terminal number 85.
²Terminal number 86 supplies voltage to the coil
side of the relay.
²When the PCM de-energizes the ASD and fuel
pump relays, terminal number 87A connects to termi-
nal 30. This is the Off position. In the off position,
voltage is not supplied to the rest of the circuit. Ter-
minal 87A is the center terminal on the relay.
²When the PCM energizes the ASD and fuel
pump relays, terminal 87 connects to terminal 30.
This is the On position. Terminal 87 supplies voltage
to the rest of the circuit.
The following procedure applies to the ASD and
fuel pump relays.
(1) Remove relay from connector before testing.
Fig. 3 TYPE 1 RELAY (ISO MICRO RELAY)
DRIGNITION CONTROL 8I - 5
IGNITION CONTROL (Continued)

(2) With the relay removed from the vehicle, use
an ohmmeter to check the resistance between termi-
nals 85 and 86. The resistance should be 75 ohms +/-
5 ohms.
(3) Connect the ohmmeter between terminals 30
and 87A. The ohmmeter should show continuity
between terminals 30 and 87A.
(4) Connect the ohmmeter between terminals 87
and 30. The ohmmeter should not show continuity at
this time.
(5) Connect one end of a jumper wire (16 gauge or
smaller) to relay terminal 85. Connect the other end
of the jumper wire to the ground side of a 12 volt
power source.
(6) Connect one end of another jumper wire (16
gauge or smaller) to the power side of the 12 volt
power source.Do not attach the other end of the
jumper wire to the relay at this time.
WARNING: DO NOT ALLOW OHMMETER TO CON-
TACT TERMINALS 85 OR 86 DURING THIS TEST.
DAMAGE TO OHMMETER MAY RESULT.
(7) Attach the other end of the jumper wire to
relay terminal 86. This activates the relay. The ohm-
meter should now show continuity between relay ter-
minals 87 and 30. The ohmmeter should not show
continuity between relay terminals 87A and 30.
(8) Disconnect jumper wires.(9) Replace the relay if it did not pass the continu-
ity and resistance tests. If the relay passed the tests,
it operates properly. Check the remainder of the ASD
and fuel pump relay circuits. Refer to 8, Wiring Dia-
grams.
REMOVAL
The ASD relay is located in the Power Distribution
Center (PDC) (Fig. 5). Refer to label on PDC cover
for relay location.
(1) Remove PDC cover.
(2) Remove relay from PDC.
(3) Check condition of relay terminals and PDC
connector terminals for damage or corrosion. Repair
if necessary before installing relay.
(4) Check for pin height (pin height should be the
same for all terminals within the PDC connector).
Repair if necessary before installing relay.
INSTALLATION
The ASD relay is located in the Power Distribution
Center (PDC) (Fig. 5). Refer to label on PDC cover
for relay location.
(1) Install relay to PDC.
(2) Install cover to PDC.
Fig. 4 ASD AND FUEL PUMP RELAY TERMINALSÐ
TYPE 2
TERMINAL LEGEND
NUMBER IDENTIFICATION
30 COMMON FEED
85 COIL GROUND
86 COIL BATTERY
87 NORMALLY OPEN
87A NORMALLY CLOSED
Fig. 5 PDC LOCATION
1 - BATTERY
2 - INTEGRATED POWER MODULE (IPM)
8I - 6 IGNITION CONTROLDR
AUTOMATIC SHUT DOWN RELAY (Continued)

CAMSHAFT POSITION SENSOR
DESCRIPTION
3.7L V-6
The Camshaft Position Sensor (CMP) on the 3.7L
6-cylinder engine is bolted to the right-front side of
the right cylinder head.
4.7L V-8
The Camshaft Position Sensor (CMP) on the 4.7L
V-8 engine is bolted to the right-front side of the
right cylinder head.
5.7L V-8
The Camshaft Position Sensor (CMP) on the 5.7L
V-8 engine is located below the generator on the tim-
ing chain / case cover on the right/front side of
engine.
5.9L Diesel
The Camshaft Position Sensor (CMP) on the 5.9L
diesel engine is located below the fuel injection
pump. It is bolted to the back of the timing gear
cover.
OPERATION
3.7L V-6
The Camshaft Position Sensor (CMP) sensor on the
3.7L V-6 engine contains a hall effect device referred
to as a sync signal generator. A rotating target wheel
(tonewheel) for the CMP is located at the front of the
camshaft for the right cylinder head (Fig. 6). This
sync signal generator detects notches located on a
tonewheel. As the tonewheel rotates, the notches
pass through the sync signal generator. The signal
from the CMP sensor is used in conjunction with the
Crankshaft Position Sensor (CKP) to differentiate
between fuel injection and spark events. It is also
used to synchronize the fuel injectors with their
respective cylinders.
When the leading edge of the tonewheel notch
enters the tip of the CMP, the interruption of mag-
netic field causes the voltage to switch high, result-
ing in a sync signal of approximately 5 volts.
When the trailing edge of the tonewheel notch
leaves then tip of the CMP, the change of the mag-
netic field causes the sync signal voltage to switch
low to 0 volts.
4.7L V-8
The CMP sensor on the 4.7L engine contains a hall
effect device called a sync signal generator to gener-
ate a fuel sync signal. This sync signal generator
detects notches located on a tonewheel. The tone-wheel is located at the front of the camshaft for the
right cylinder head (Fig. 7). As the tonewheel rotates,
the notches pass through the sync signal generator.
The pattern of the notches (viewed counter-clockwise
from front of engine) is: 1 notch, 2 notches, 3 notches,
3 notches, 2 notches 1 notch, 3 notches and 1 notch.
The signal from the CMP sensor is used in conjunc-
tion with the crankshaft position sensor to differenti-
ate between fuel injection and spark events. It is also
used to synchronize the fuel injectors with their
respective cylinders.
5.7L V-8
The CMP sensor is used in conjunction with the
crankshaft position sensor to differentiate between
fuel injection and spark events. It is also used to syn-
chronize the fuel injectors with their respective cylin-
ders. The sensor generates electrical pulses. These
pulses (signals) are sent to the Powertrain Control
Module (PCM). The PCM will then determine crank-
shaft position from both the camshaft position sensor
and crankshaft position sensor.
The tonewheel is located at the front of the cam-
shaft (Fig. 8). As the tonewheel rotates, notches (Fig.
8) pass through the sync signal generator.
When the cam gear is rotating, the sensor will
detect the notches. Input voltage from the sensor to
the PCM will then switch from a low (approximately
0.3 volts) to a high (approximately 5 volts). When the
sensor detects a notch has passed, the input voltage
switches back low to approximately 0.3 volts.
Fig. 6 CMP OPERATION- 3.7L V-6
1 - NOTCHES
2 - RIGHT CYLINDER HEAD
3 - CMP
4 - TONEWHEEL (TARGET WHEEL)
DRIGNITION CONTROL 8I - 7

5.9L Diesel
The Camshaft Position Sensor (CMP) contains a
hall effect device. A rotating target wheel (tonewheel)
for the CMP is located on the front timing gear. This
hall effect device detects notches located on the tone-
wheel. As the tonewheel rotates, the notches pass the
tip of the CMP.
When the leading edge of the tonewheel notch
passes the tip of the CMP, the following occurs: The
interruption of magnetic field causes the voltage to
switch high resulting in a signal of approximately 5
volts.
When the trailing edge of the tonewheel notch
passes the tip of the CMP, the following occurs: The
change of the magnetic field causes the signal voltage
to switch low to 0 volts.
The CMP (Fig. 9) provides a signal to the Engine
Control Module (ECM) at all times when the engine
is running. The ECM uses the CMP information pri-
marily on engine start-up. Once the engine is run-
ning, the ECM uses the CMP as a backup sensor for
engine speed. The Crankshaft Position Sensor (CKP)
is the primary engine speed indicator for the engine
after the engine is running.
Fig. 7 CMP AND TONEWHEEL OPERATION - 4.7L
V-8
1 - NOTCHES
2 - RIGHT CYLINDER HEAD
3 - CAMSHAFT POSITION SENSOR
4 - TONEWHEEL
Fig. 8 CMP OPERATION - 5.7L ENGINE
1 - TIMING CHAIN COVER
2 - TONEWHEEL
3 - NOTCHES
Fig. 9 5.9L DIESEL CMP
1 - CMP
2 - FUEL INJECTION PUMP (BOTTOM)
3 - ELECTRONIC CONTROL MODULE (ECM)
4 - ECM ELEC. CONNECTOR
5 - CMP ELEC. CONNECTOR
6 - CMP MOUNTING BOLT
7 - BACK OF TIMING GEAR COVER
8I - 8 IGNITION CONTROLDR
CAMSHAFT POSITION SENSOR (Continued)

5.9L Diesel
The Camshaft Position Sensor (CMP) on the 5.9L
diesel engine is located below the fuel injection
pump. It is bolted to the back of the timing gear
cover (Fig. 14).
(1) Disconnect electrical connector at CMP sensor
(Fig. 14).
(2) Remove sensor mounting bolt.
(3) Carefully twist sensor from timing gear cover.
(4) Check condition of sensor o-ring.
INSTALLATION
3.7L V-6
The Camshaft Position Sensor (CMP) on the 3.7L
V-6 engine is bolted to the front/top of the right cyl-
inder head (Fig. 10).
(1) Clean out machined hole in cylinder head.
(2) Apply a small amount of engine oil to sensor
o-ring.
(3) Install sensor into cylinder head with a slight
rocking and twisting action.
CAUTION: Before tightening sensor mounting bolt,
be sure sensor is completely flush to cylinder head.
If sensor is not flush, damage to sensor mounting
tang may result.
(4) Install mounting bolt and tighten. Refer to
torque specifications.(5) Connect electrical connector to sensor.
4.7L V-8
The Camshaft Position Sensor (CMP) on the 4.7L
V-8 engine is bolted to the front/top of the right cyl-
inder head (Fig. 11).
(1) Clean out machined hole in cylinder head.
(2) Apply a small amount of engine oil to sensor
o-ring.
(3) Install sensor into cylinder head with a slight
rocking action. Do not twist sensor into position as
damage to o-ring may result.
CAUTION: Before tightening sensor mounting bolt,
be sure sensor is completely flush to cylinder head.
If sensor is not flush, damage to sensor mounting
tang may result.
(4) Install mounting bolt and tighten. Refer to
Torque Specifications.
(5) Connect electrical connector to sensor.
5.7L V-8
The Camshaft Position Sensor (CMP) on the 5.7L
V-8 engine is bolted to the right / front side of the
timing chain cover (Fig. 12) or (Fig. 13).
(1) Clean out machined hole in cylinder head.
Fig. 13 CMP REMOVAL / INSTALLATION ± 5.7L V-8
1 - TIMING CHAIN COVER (RIGHT/FRONT)
2 - CMP SENSOR
3 - MOUNTING BOLT
Fig. 14 5.9L DIESEL CMP
1 - CMP
2 - FUEL INJECTION PUMP (BOTTOM)
3 - ELECTRONIC CONTROL MODULE (ECM)
4 - ECM ELEC. CONNECTOR
5 - CMP ELEC. CONNECTOR
6 - CMP MOUNTING BOLT
7 - BACK OF TIMING GEAR COVER
8I - 10 IGNITION CONTROLDR
CAMSHAFT POSITION SENSOR (Continued)