1998 DODGE RAM 1500 heating

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)

ELECTRODE GAP BRIDGING
Electrode gap bridging may be traced to loose
deposits in the combustion chamber. These deposits
accumulate on the spark plugs during continuous
stop-and-go driving. When the engine is suddenly
subjected to a high torque load, deposits partially liq-
uefy and bridge the gap between electrodes (Fig. 25).
This short circuits the electrodes. Spark plugs with
electrode gap bridging can be cleaned using standard
procedures.
SCAVENGER DEPOSITS
Fuel scavenger deposits may be either white or yel-
low (Fig. 26). They may appear to be harmful, but
this is a normal condition caused by chemical addi-
tives in certain fuels. These additives are designed to
change the chemical nature of deposits and decrease
spark plug misfire tendencies. Notice that accumula-
tion on the ground electrode and shell area may be
heavy, but the deposits are easily removed. Spark
plugs with scavenger deposits can be considered nor-
mal in condition and can be cleaned using standard
procedures.
CHIPPED ELECTRODE INSULATOR
A chipped electrode insulator usually results from
bending the center electrode while adjusting the
spark plug electrode gap. Under certain conditions,
severe detonation can also separate the insulator
from the center electrode (Fig. 27). Spark plugs with
this condition must be replaced.
PREIGNITION DAMAGE
Preignition damage is usually caused by excessive
combustion chamber temperature. The center elec-
trode dissolves first and the ground electrode dis-
solves somewhat latter (Fig. 28). Insulators appear
relatively deposit free. Determine if the spark plug
has the correct heat range rating for the engine.
Determine if ignition timing is over advanced or if
other operating conditions are causing engine over-
heating. (The heat range rating refers to the operat-
ing temperature of a particular type spark plug.
Spark plugs are designed to operate within specific
temperature ranges. This depends upon the thick-
ness and length of the center electrodes porcelain
insulator.)
Fig. 24 OIL OR ASH ENCRUSTED
Fig. 25 ELECTRODE GAP BRIDGING
1 - GROUND ELECTRODE
2 - DEPOSITS
3 - CENTER ELECTRODE
Fig. 26 SCAVENGER DEPOSITS
1 - GROUND ELECTRODE COVERED WITH WHITE OR YELLOW
DEPOSITS
2 - CENTER ELECTRODE
8I - 18 IGNITION CONTROLDR
SPARK PLUG (Continued)

SPARK PLUG OVERHEATING
Overheating is indicated by a white or gray center
electrode insulator that also appears blistered (Fig.
29). The increase in electrode gap will be consider-
ably in excess of 0.001 inch per 2000 miles of opera-
tion. This suggests that a plug with a cooler heat
range rating should be used. Over advanced ignition
timing, detonation and cooling system malfunctions
can also cause spark plug overheating.
REMOVAL
3.7L V-6
Each individual spark plug is located under each
ignition coil. Each individual ignition coil must be
removed to gain access to each spark plug. Refer to
Ignition Coil Removal/Installation.(1) Remove necessary air filter tubing at throttle
body.
(2) Prior to removing ignition coil, spray com-
pressed air around coil base at cylinder head.
(3) Prior to removing spark plug, spray com-
pressed air into cylinder head opening. This will help
prevent foreign material from entering combustion
chamber.
(4) Remove spark plug from cylinder head using a
quality socket with a rubber or foam insert. Also
check condition of ignition coil o-ring and replace as
necessary.
(5) Inspect spark plug condition. Refer to Diagnos-
tics and Testing - Spark Plug Conditions.
4.7L V-8
Each individual spark plug is located under each
ignition coil. Each individual ignition coil must be
removed to gain access to each spark plug. Refer to
Ignition Coil Removal/Installation.
(1) Remove necessary air filter tubing at throttle
body.
(2) Prior to removing ignition coil, spray com-
pressed air around coil base at cylinder head.
(3) Prior to removing spark plug, spray com-
pressed air into cylinder head opening. This will help
prevent foreign material from entering combustion
chamber.
(4) Remove spark plug from cylinder head using a
quality socket with a rubber or foam insert. Also
check condition of ignition coil o-ring and replace as
necessary.
(5) Inspect spark plug condition. Refer to Diagnos-
tics and Testing - Spark Plug Conditions.
5.7L V-8
Eight of the 16 spark plugs are located under an
ignition coil; the other 8 are not. If spark plug being
Fig. 27 CHIPPED ELECTRODE INSULATOR
1 - GROUND ELECTRODE
2 - CENTER ELECTRODE
3 - CHIPPED INSULATOR
Fig. 28 PREIGNITION DAMAGE
1 - GROUND ELECTRODE STARTING TO DISSOLVE
2 - CENTER ELECTRODE DISSOLVED
Fig. 29 SPARK PLUG OVERHEATING
1 - BLISTERED WHITE OR GRAY COLORED INSULATOR
DRIGNITION CONTROL 8I - 19
SPARK PLUG (Continued)

POWER MIRRORS
TABLE OF CONTENTS
page page
POWER MIRRORS
DESCRIPTION.........................10
OPERATION...........................10
DIAGNOSIS AND TESTING - POWER
MIRRORS...........................10
AUTOMATIC DAY / NIGHT MIRROR
DESCRIPTION.........................11
OPERATION...........................11
DIAGNOSIS AND TESTING - AUTOMATIC DAY
/ NIGHT MIRROR......................11REMOVAL.............................12
POWER MIRROR SWITCH
DIAGNOSIS AND TESTING - POWER MIRROR
SWITCH............................12
REMOVAL.............................12
SIDEVIEW MIRROR
REMOVAL.............................12
POWER MIRRORS
DESCRIPTION
AUTOMATIC DAY/NIGHT MIRROR
The automatic day/night mirror system is able to
automatically change the reflectance of the inside
rear view mirror in order to reduce the glare of head-
lamps approaching the vehicle from the rear. The
automatic day/night rear view mirror receives bat-
tery current through a fuse in the Integrated Power
Module (IPM) only when the ignition switch is in the
On position.
OUTSIDE REAR VIEW MIRROR
The power operated outside rear view mirrors
allow the driver to adjust both outside mirrors elec-
trically from the driver side front seat position by
operating a switch on the driver side front door trim
panel. The power mirrors receive a non-switched bat-
tery feed through a fuse in the Integrated Power
Module (IPM) so that the system will remain opera-
tional, regardless of the ignition switch position.
OPERATION
AUTOMATIC DAY/NIGHT MIRROR
A switch located on the bottom of the automatic
day/night mirror housing allows the vehicle operator
to select whether the automatic dimming feature is
operational. When the automatic day/night mirror is
turned on, the mirror switch is lighted by an integral
Light-Emitting Diode (LED). The mirror will auto-
matically disable its self-dimming feature whenever
the vehicle is being driven in reverse.
OUTSIDE REAR VIEW MIRROR
The heated mirrors include an electric heating grid
behind the mirror glass in each outside mirror, which
can clear the mirror glass of ice, snow, or fog. (Refer
to 8 - ELECTRICAL/HEATED MIRRORS -
DESCRIPTION) for more information.
DIAGNOSIS AND TESTING - POWER MIRRORS
WIRING VOLTAGE TEST
The following wiring test determines whether or
not voltage is continuous through the body harness
to switch.
(1) Remove the power mirror switch (Refer to 8 -
ELECTRICAL/POWER LOCKS/DOOR MODULE -
REMOVAL).
(2) Disconnect wire harness connector from back of
power mirror switch.
(3) Connect the clip end of a 12 volt test light to
Pin 5 in the mirror switch harness connector. Touch
the test light probe to Pin 3.
If the test light illuminates, the wiring circuit
between the battery and switch is OK.
If the lamp does not illuminate, first check fuse in
the Integrated Power Module (IPM). If fuse is OK,
then check for a broken wire.
Refer to the appropriate wiring information.
POWER MIRROR MOTOR TEST
If the power mirror switch is receiving proper cur-
rent and ground and mirrors do not operate, proceed
with power mirror motor test. Refer to the appropri-
ate wiring information.
(1) Remove the power mirror switch (Refer to 8 -
ELECTRICAL/POWER LOCKS/DOOR MODULE -
REMOVAL).
8N - 10 POWER MIRRORSDR

SPECIAL TOOLS
POWER DISTRIBUTION SYSTEMS
CIGAR LIGHTER OUTLET
DESCRIPTION
On models equipped a cigar lighter outlet is
installed to the left of the center stack area in the
lower instrument panel. The cigar lighter outlet is
secured by a snap fit within the bezel.
The cigar lighter outlet, plastic cap and the knob
and heating element unit are available for service
replacement. These components cannot be repaired
and, if faulty or damaged, they must be replaced.
OPERATION
The cigar lighter consists of two major components:
a knob and heating element unit, and the cigar
lighter base or outlet shell. The receptacle shell is
connected to ground, and an insulated contact in the
bottom of the shell is connected to battery current.
The cigar lighter receives battery voltage from a fuse
in the junction block when the ignition switch is in
the Accessory or Run positions.
The cigar lighter knob and heating element are
encased within a spring-loaded housing, which also
features a sliding protective heat shield. When the
knob and heating element are inserted in the outlet
shell, the heating element resistor coil is grounded
through its housing to the outlet shell. If the cigar
lighter knob is pushed inward, the heat shield slides
up toward the knob exposing the heating element,
and the heating element extends from the housing
toward the insulated contact in the bottom of the
outlet shell.
Two small spring-clip retainers are located on
either side of the insulated contact inside the bottom
of the outlet shell. These clips engage and hold the
heating element against the insulated contact longenough for the resistor coil to heat up. When the
heating element is engaged with the contact, battery
current can flow through the resistor coil to ground,
causing the resistor coil to heat.
When the resistor coil becomes sufficiently heated,
excess heat radiates from the heating element caus-
ing the spring-clips to expand. Once the spring-clips
expand far enough to release the heating element,
the spring-loaded housing forces the knob and heat-
ing element to pop back outward to their relaxed
position. When the cigar lighter knob and element
are pulled out of the outlet shell, the protective heat
shield slides downward on the housing so that the
heating element is recessed and shielded around its
circumference for safety.
DIAGNOSIS AND TESTING - CIGAR LIGHTER
OUTLET
For complete circuit diagrams, refer toWiring
Diagrams.
(1) Check the fused B(+) fuse in the integrated
power module. If OK, go to Step 2. If not OK, repair
the shorted circuit or component as required and
replace the faulty fuse.
(2) Turn the ignition switch to the Run position.
Check for battery voltage at the fused B(+) fuse in
the integrated power module. If OK, go to Step 3. If
not OK, repair the open or short as required.
(3) Remove the cigar lighter knob and element
from the cigar lighter outlet shell. Check for continu-
ity between the inside circumference of the cigar
lighter outlet shell and a good ground. there should
be continuity. If OK, go to Step 4. If not OK, go to
Step 5.
(4) Turn the ignition switch to the Run position.
Check for battery voltage at the insulated contact
located at the back of the cigar lighter outlet shell. If
OK, replace the faulty cigar lighter knob and ele-
ment. If not OK, go to Step 5.
(5) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Check for continuity between the ground circuit cav-
ity of the cigar lighter wire harness connector and a
good ground. There should be continuity. If OK, go to
Step 6. If not OK, repair the open ground circuit to
ground as required.
(6) Connect the battery negative cable. Turn the
ignition switch to the Accessory or Run positions.
Check for battery voltage at the fused B(+) circuit
cavity of the cigar lighter wire harness connector. If
OK, replace the faulty cigar lighter outlet. If not OK,
repair the open fused B(+) circuit to the integrated
power module fuse as required.Terminal Pick Kit 6680
8W - 97 - 2 8W-97 POWER DISTRIBUTIONDR
POWER DISTRIBUTION (Continued)

becomes transparent and the fuse that has been
assigned the IOD designation becomes only another
Fused B(+) circuit fuse.
The IOD fuse can be used by the vehicle owner as
a convenient means of reducing battery depletion
when a vehicle is to be stored for periods not to
exceed about thirty days. However, it must be
remembered that disconnecting the IOD fuse will not
eliminate IOD, but only reduce this normal condition.
If a vehicle will be stored for more than about thirty
days, the battery negative cable should be discon-
nected to eliminate normal IOD; and, the battery
should be tested and recharged at regular intervals
during the vehicle storage period to prevent the bat-
tery from becoming discharged or damaged.
REMOVAL
The Ignition-Off Draw (IOD) fuse is disconnected
from Integrated Power Module fuse cavity # 51 when
the vehicle is shipped from the assembly plant.
Dealer personnel must reconnect the IOD fuse when
the vehicle is being prepared for delivery in order to
restore full electrical system operation.
(1) Turn the ignition switch to the Off position.
(2) Remove the Integrated Power Module cover.
(3) Grasp the outer tabs of the IOD fuse holder
unit in fuse cavity # 51 between the thumb and fore-
finger and pull the unit firmly upward.
(4) Install the Integrated Power Module cover.
INSTALLATION
(1) Turn the ignition switch to the Off position.
(2) Remove the Integrated Power Module cover.
(3) To install the IOD fuse, use a thumb to press
the IOD fuse holder unit in fuse cavity # 51 firmly
into the Integrated Power Module.
(4) Install the Integrated Power Module cover.
POWER OUTLET
DESCRIPTION
Two power outlets are utilized on this model. One
in the instrument panel center lower bezel and the
other in the center console. The power outlet bases
are secured by a snap fit within the instrument
panel or trim panel. A plastic protective cap snaps
into the power outlet base when the power outlet is
not being used, and hangs from the power outlet base
mount by an integral bail strap while the power out-
let is in use.The power outlet receptacle unit and the accessory
power outlet protective cap are available for service.
The power outlet receptacle cannot be repaired and,
if faulty or damaged, it must be replaced.
OPERATION
The power outlet base or receptacle shell is con-
nected to ground, and an insulated contact in the
bottom of the shell is connected to battery current.
The power outlet receives battery voltage from a fuse
in the integrated power module at all times.
While the power outlet is very similar to a cigar
lighter base unit, it does not include the two small
spring-clip retainers inside the bottom of the recepta-
cle shell that are used to secure the cigar lighter
heating element to the insulated contact.
DIAGNOSIS AND TESTING - POWER OUTLET
For complete circuit diagrams, refer toWiring
Diagrams.
(1) Check the fused B(+) fuse in the integrated
power module. If OK, go to Step 2. If not OK, repair
the shorted circuit or component as required and
replace the faulty fuse.
(2) Check for battery voltage at the fused B(+) fuse
in the integrated power module. If OK, go to Step 3.
If not OK, repair the open fused B(+) circuit to the
battery as required.
(3) Remove the plastic protective cap from the
power outlet receptacle. Check for continuity between
the inside circumference of the power outlet recepta-
cle and a good ground. There should be continuity. If
OK, go to Step 4. If not OK, go to Step 5.
(4) Check for battery voltage at the insulated con-
tact located at the back of the power outlet recepta-
cle. If not OK, go to Step 5.
(5) Disconnect and isolate the battery negative
cable. Remove the power outlet receptacle from the
instrument panel. Disconnect the wire harness con-
nector from the power outlet receptacle. Check for
continuity between the ground circuit cavity of the
power outlet wire harness connector and a good
ground. There should be continuity. If OK, go to Step
6. If not OK, repair the open ground circuit to ground
as required.
(6) Connect the battery negative cable. Check for
battery voltage at the fused B(+) circuit cavity of the
power outlet wire harness connector. If OK, replace
the faulty power outlet receptacle. If not OK, repair
the open fused B(+) circuit to the integrated power
module fuse as required.
DR8W-97 POWER DISTRIBUTION 8W - 97 - 7
IOD FUSE (Continued)

AIR CLEANER ELEMENT
REMOVAL
Filter Element Only
Housing removal is not necessary for element (fil-
ter) replacement.
(1) Loosen clamp (Fig. 3) and disconnect air duct
at air cleaner cover.
(2) Pry over 4 spring clips (Fig. 3) from housing
cover (spring clips retain cover to housing).
(3) Release housing cover from locating tabs on
housing (Fig. 3) and remove cover.
(4) Remove air cleaner element (filter) from hous-
ing.
(5) Clean inside of housing before replacing ele-
ment.
Housing Assembly
(1) Loosen clamp (Fig. 3) and disconnect air duct
at air cleaner cover.
(2) Lift entire housing assembly from 4 locating
pins (Fig. 4).
INSTALLATION
(1) Install filter element into housing.
(2) Position housing cover into housing locating
tabs (Fig. 3).(3) Pry up 4 spring clips (Fig. 3) and lock cover to
housing.
(4) Install air duct to air cleaner cover and tighten
hose clamp to 3 N´m (30 in. lbs.) torque.
(5) If any other hose clamps were removed from
air intake system, tighten them to 3.4 N´m (30 in.
lbs.) torque.
(6) If any bolts were removed from air resonator
housing or air intake tubing, tighten them to 4.5 N´m
(40 in. lbs.) torque.
CYLINDER HEAD - LEFT
DIAGNOSIS AND TESTING - CYLINDER HEAD
GASKET
A cylinder head gasket leak can be located between
adjacent cylinders or between a cylinder and the
adjacent water jacket.
Possible indications of the cylinder head gasket
leaking between adjacent cylinders are:
²Loss of engine power
²Engine misfiring
²Poor fuel economy
Possible indications of the cylinder head gasket
leaking between a cylinder and an adjacent water
jacket are:
²Engine overheating
²Loss of coolant
Fig. 3 AIR CLEANER HOUSING COVER
1 - CLAMP
2 - AIR DUCT
3 - AIR CLEANER COVER
4 - LOCATING TABS
5 - CLIPS (4)
Fig. 4 AIR CLEANER HOUSING
1 - AIR CLEANER HOUSING ASSEMBLY
2 - LOCATING PINS (4)
DRENGINE - 3.7L 9 - 21

(19) Disconnect throttle and speed control cables.
(20) Disconnect tube from both the left and right
side crankcase breathers (Fig. 2). Remove breathers
(21) Discharge A/C system (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING/REFRIG-
ERANT - STANDARD PROCEDURE).
(22) Remove A/C compressor (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING/A/C COM-
PRESSOR - REMOVAL).
(23) Remove shroud, fan assembly (Refer to 7 -
COOLING/ENGINE/FAN DRIVE VISCOUS
CLUTCH - REMOVAL) and accessory drive belt
(Refer to 7 - COOLING/ACCESSORY DRIVE/DRIVE
BELTS - REMOVAL).
(24) Disconnect transmission oil cooler lines at the
radiator.
(25) Disconnect radiator upper and lower hoses.
(26) Remove radiator (Refer to 7 - COOLING/EN-
GINE/RADIATOR - REMOVAL), A/C condenser
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING/A/C CONDENSER - REMOVAL) and
transmission oil cooler.
(27) Remove generator (Refer to 8 - ELECTRICAL/
CHARGING/GENERATOR - REMOVAL).
(28) Disconnect the two heater hoses from the tim-
ing chain cover and heater core.
(29) Unclip and remove heater hoses and tubes
from the intake manifold.
(30) Disconnect engine harness at the following
points :
²Intake air temperature (IAT) sensor (Fig. 3)
²Fuel Injectors
²Throttle Position (TPS) Switch
²Idle Air Control (IAC) Motor
²Engine Oil Pressure Switch
²Engine Coolant Temperature (ECT) Sensor
²Manifold absolute pressure (MAP) Sensor
²Camshaft Position (CMP) Sensor
²Coil Over Plugs(31) Disconnect the vacuum lines at the throttle
body and intake manifold.
(32) Release fuel rail pressure (Refer to 14 - FUEL
SYSTEM/FUEL DELIVERY - STANDARD PROCE-
DURE) then disconnect the fuel supply quick connect
fitting at the fuel rail (Refer to 14 - FUEL SYSTEM/
FUEL DELIVERY/QUICK CONNECT FITTING -
STANDARD PROCEDURE).
(33) Remove power steering pump and position out
of the way.
(34) Install Special Tools 8400 Lifting Studs, into
the cylinder heads.
(35) Install Engine Lifting Fixture Special Tool
8347 (Fig. 4) following these steps.
²Holding the lifting fixture at a slight angle, slide
the large bore in the front plate over the hex portion
of the lifting stud.
²Position the two remaining fixture arms onto
the two Special Tools 8400 Lifting Studs, in the cyl-
inder heads.
²Pull foward and upward on the lifting fixture so
that the lifting stud rest in the slotted area below the
large bore.
Fig. 2 Crankcase Breather Connection Points
1 - CRANKCASE BREATHERS
Fig. 3 Throttle Body Connection Points
1 - THROTTLE BODY
2 - TPS
3 - IAC MOTOR
4 - IAT SENSOR
5 - MOUNTING SCREWS
9 - 96 ENGINE - 4.7LDR
ENGINE - 4.7L (Continued)