1998 DODGE RAM 1500 Tire

ACCELERATOR PEDAL
POSITION SENSOR
DESCRIPTION
The Accelerator Pedal Position Sensor (APPS)
assembly is located under the vehicle battery tray. A
cable connects the assembly to the accelerator pedal.
A plastic cover with a movable door is used to cover
the assembly.
The APPS is used only with the 5.7L V-8 engine.
OPERATION
The Accelerator Pedal Position Sensor (APPS) is a
linear potentiometer. It provides the Powertrain Con-
trol Module (PCM) with a DC voltage signal propor-
tional to the angle, or position of the accelerator
pedal. The APPS signal is translated (along with
other sensors) to place the throttle plate (within the
throttle body) to a pre-determined position.
A mechanical cable is used between the accelerator
pedal and the APPS assembly. Although a cable is
used between the pedal and APPS, a mechanical
cable is not used at the throttle body. Throttle plate
position is electrically determined.
REMOVAL
The APPS is serviced (replaced) as one assembly
including the sensor, plastic housing and cable. The
APPS assembly is located under the vehicle battery
tray (Fig. 2). Access to APPS is gained from over top
of left / front tire.
(1) Disconnect negative battery cable at battery.
(2) Disconnect APPS cable at accelerator pedal.
Refer to Accelerator Pedal Removal / Installation.
(3) Remove wheel house liner at left / front wheel.
Refer to Body.
(4) Gain access to APPS electrical connector by
opening swing-down door (Fig. 3). Disconnect electri-
cal connector.
(5) Remove 3 mounting bolts (Fig. 3).
(6) Remove APPS assembly from battery tray.
(7) If cable is to be separated at APPS, unsnap
cable clip from ball socket (Fig. 4). Release cable from
plastic housing by pressing on small cable release tab
(Fig. 3).
INSTALLATION
(1) Install Accelerator Pedal Position Sensor
(APPS) cable to accelerator pedal. Refer to Accelera-
tor Pedal Removal / Installation.
(2) Connect electrical connector to APPS.
(3) If necessary, connect cable to APPS lever ball
socket (snaps on).
(4) Snap APPS cable cover closed.
Fig. 1 ACCELERATOR PEDAL MOUNTING
1 - ACCELERATOR CABLE
2 - PLASTIC RETAINER (CLIP)
3 - THROTTLE PEDAL ARM
4 - PEDAL / BRACKET ASSEMBLY
5 - CABLE CLIP
Fig. 2 APPS LOCATION
1 - BATTERY TRAY
2 - APPS LOCATION
3 - APPS MOUNTING BOLTS
14 - 22 FUEL INJECTION - GASDR
ACCELERATOR PEDAL (Continued)

FUEL TANK
DESCRIPTION - DIESEL
The fuel tank is similar to the tank used with gas-
oline powered models. The tank is equipped with a
separate fuel return line and a different fuel tank
module for diesel powered models. A fuel tank
mounted, electric fuel pump is not used with diesel
powered models. Refer to Fuel Tank Module for addi-
tional information.
REMOVAL - DIESEL
Fuel Tank Draining
Due to a one-way check valve installed into the
fuel fill opening fitting at the tank, the tank cannot
be drained conventionally at the fill cap.
(1) Raise vehicle.
(2) If vehicle is equipped with 4 doors and a 6 foot
(short) box, remove left-rear tire/wheel.
(3) Thoroughly clean area at top of fuel tank
around fuel tank module.
(4) Remove rubber cap from auxiliary fitting on
top of tank module (Fig. 19).
(5) Drain fuel tank by attaching drain hose from
an approved draining station to auxiliary fitting on
top of tank module (Fig. 19).
Tank Removal
(1) Loosen clamp and disconnect rubber fuel fill
hose at tank.
(2) Support tank with a hydraulic jack.
(3) Remove 2 fuel tank strap nuts (Fig. 20) and
remove both tank support straps.
(4) Carefully lower tank a few inches and discon-
nect fuel pump module electrical connector (Fig. 19)
at top of tank. To disconnect electrical connector:
Push upward on red colored tab to unlock. Push on
black colored tab while removing connector.
(5) Disconnect fuel supply and return lines at fuel
tank module (Fig. 19). Refer to Quick-Connect Fit-
tings for procedures.
(6) Continue to lower tank for removal.
(7) If fuel tank is to be replaced, remove fuel tank
module from tank. Refer to Fuel Tank Module
Removal/Installation procedures.INSTALLATION - DIESEL
(1) If fuel tank is to be replaced, install fuel tank
module into tank. Refer to Fuel Tank Module Remov-
al/Installation procedures.
(2) Position fuel tank to hydraulic jack.
(3) Raise tank until positioned near body.
(4) Connect fuel tank module electrical connector
at top of tank.
(5) Connect fuel supply and return lines to tank
module.
(6) Continue raising tank until positioned snug to
body.
(7) Install and position both tank support straps.
Install 2 fuel tank strap nuts and tighten.Tighten
rear strap nut first.Refer to Torque Specifications.
(8) Remove hydraulic jack.
(9) Connect rubber fill hose to fuel fill tube and
tighten clamp.
(10) Install tire / wheel (if necessary).
(11) Lower vehicle.
(12) Fill fuel tank with fuel.
(13) Start engine and check for fuel leaks near top
of module.
Fig. 19 FUEL TANK MODULE - DIESEL
1 - TOP OF FUEL TANK
2 - AUX. FITTING
3 - ELEC. CONNECTOR
4 - FUEL TANK MODULE (TOP)
5 - LOCKNUT
6 - FUEL SUPPLY LINE
7 - FUEL RETURN LINE
14 - 62 FUEL DELIVERY - DIESELDR

CAUTION: Do not attempt to remove sensor from
its mounting bracket as electronic calibration will
be destroyed (sensor-to-bracket mounting screws
are permanently attached). Two accelerator lever
set screws (Fig. 3) are used to position lever. Do
not attempt to alter positions of these set screws as
electronic calibration will be destroyed.
(1) Disconnect both negative battery cables at both
batteries.
(2) Remove cable cover (Fig. 1). Cable cover is
attached with 2 Phillips screws, 2 plastic retention
clips and 2 push tabs (Fig. 1). Remove 2 Phillips
screws and carefully pry out 2 retention clips. After
clip removal, push rearward on front tab, and
upward on lower tab for cover removal.
(3) Using finger pressure only, disconnect end of
speed control servo cable from throttle lever pin by
pulling forward on connector while holding lever
rearward (Fig. 2).DO NOT try to pull connector
off perpendicular to lever pin. Connector will
be broken.
(4) Using two small screwdrivers, pry throttle
cable connector socket from throttle lever ball (Fig.
2).Be very careful not to bend throttle lever
arm.
(5) Disconnect transmission control cable at lever
arm (if equipped). Refer to 21, Transmission.
(6) Squeeze pinch tabs on speed control cable (Fig.
2) and pull cable rearward to remove from cable
mounting bracket.
(7) Squeeze pinch tabs on throttle cable (Fig. 2)
and pull cable rearward to remove from cable mount-
ing bracket.
(8) Refer to 21, Transmission for transmission con-
trol cable removal procedures.
(9) Disconnect wiring harness clip (Fig. 3) at bot-
tom of bracket.
(10) Remove 6 mounting bolts (Fig. 3) and par-
tially remove APPS assembly from engine. After
assembly is partially removed, disconnect electrical
connector from bottom of sensor by pushing on con-
nector tab (Fig. 4).
(11) Remove APPS assembly from engine.
Battery Tray Mounted Sensor :
The APPS is serviced (replaced) as one assembly
including the sensor, plastic housing and cable. The
APPS assembly is located under the left (drivers
side) vehicle battery tray (Fig. 5). Access to APPS is
gained from over top of left / front tire.
(1) Disconnect negative battery cable at battery.
(2) Disconnect APPS cable at accelerator pedal.
Refer to Accelerator Pedal Removal / Installation.
(3) Remove wheel house liner at left / front wheel.
Refer to Body.(4) Gain access to APPS electrical connector by
opening swing-down door (Fig. 6). Disconnect electri-
cal connector.
(5) Remove 3 mounting bolts (Fig. 6).
(6) Remove APPS assembly from battery tray.
Fig. 1 CABLE/LEVER/THROTTLE LINKAGE COVER
1 - CABLE/LEVER/LINKAGE COVER
2 - PUSH UP LOWER TAB
3 - SCREWS/CLIPS (2)
4 - TAB PUSH HERE
Fig. 2 SERVO CABLE AT THROTTLE LEVER
1 - PINCH (2) TABS
2 - CABLE MOUNTING BRACKET
3 - PINCH TABS (2)
4 - OFF
5 - THROTTLE CABLE
6 - THROTTLE LEVER
7 - THROTTLE LEVER PIN
8 - OFF
9 - CONNECTOR
10 - SPEED CONTROL CABLE
DRFUEL INJECTION - DIESEL 14 - 69
ACCELERATOR PEDAL POSITION SENSOR (Continued)

INTAKE AIR HEATER
DESCRIPTION
The intake manifold air heater element assembly
is located in the top of the intake manifold.
OPERATION
The air heater elements are used to heat incoming
air to the intake manifold. This is done to help
engine starting and improve driveability with cool or
cold outside temperatures.
Electrical supply for the 2 air heater elements is
controlled by the Engine Control Module (ECM)
through the 2 air heater relays. Refer to Intake Man-
ifold Air Heater Relays for more information.
Two heavy-duty cables connect the 2 air heater ele-
ments to the 2 air heater relays. Each of these cables
will supply approximately 95 amps at 12 volts to an
individual heating element within the heater block
assembly.
Refer to the Powertrain Diagnostic Procedures
manual for electrical operation and complete descrip-
tion of the intake heaters, including pre-heat and
post-heat cycles.
REMOVAL
If servicing either of the heater elements, the
entire block/element assembly must be replaced.
(1) Disconnect both negative battery cables at both
batteries. Cover and isolate ends of both cables.
(2) Remove both the intake manifold air intake
tube (above injection pump), and its rubber connector
hose (Fig. 26).
(3) Lift 2 rubber covers (Fig. 27) to gain access to 2
positive (+) cable nuts. Remove these 2 nuts (Fig. 28)
and remove 2 cables from studs.
(4) Disconnect ground strap (Fig. 27) at heater ele-
ment stud.
(5) Remove wiring harness clips.
(6) Remove engine oil dipstick tube bracket from
air inlet connection and fuel filter housing.
(7) Remove 4 housing mounting bolts (Fig. 27) and
remove heater element assembly.
INSTALLATION
If servicing either of the heater elements, the
entire block/element assembly must be replaced.
(1) Using 2 new gaskets, position element assem-
bly and air housing to intake manifold.
(2) Install ground cable to air housing.
(3) Install 4 housing bolts and tighten to 24 N´m
(18 ft. lbs.) torque.
(4) Connect 2 positive (+) heater cables at cable
mounting studs.Do not allow either of the cable
eyelets to contact any other metal source other
than the cable nuts/studs.
Fig. 24 INLET/PRESSURE SENSOR REMOVAL/
INSTALLATION
1 - INLET/PRESSURE SENSOR
2 - ELEC. CONNECTOR
3 - SENSOR MOUNTING SCREWS (2)
4 - TOP OF AIR FILTER COVER
Fig. 25 SENSOR O-RING
1 - IAT/PRESSURE SENSOR
2 - O-RING
14 - 80 FUEL INJECTION - DIESELDR
INLET AIR TEMPERATURE SENSOR/PRESSURE SENSOR (Continued)

DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - POWER STEERING
SYSTEM
There is some noise in all power steering systems. One of the most common is a hissing sound evident at a
standstill parking. Or when the steering wheel is at the end of it's travel. Hiss is a high frequency noise similar
to that of a water tap being closed slowly. The noise is present in all valves that have a high velocity fluid passing
through an orifice. There is no relationship between this noise and steering performance.
STEERING NOISE
CONDITION POSSIBLE CAUSES CORRECTION
OBJECTIONAL HISS OR
WHISTLE1. Steering intermediate shaft to dash panel
seal.1. Check and repair seal at dash
panel.
2. Noisy valve in power steering gear. 2. Replace steering gear.
RATTLE OR CLUNK 1. Gear mounting bolts loose. 1. Tighten bolts to specification.
2. Loose or damaged suspension
components.2. Inspect and repair suspension.
3. Internal gear noise. 3. Replace steering gear.
4. Pressure hose in contact with other
components.4. Reposition hose.
5. Loose or damaged intermediate shaft or
column.5. Inspect and repair or replace.
CHIRP OR SQUEAL 1. Loose belt. 1. Adjust or replace.
WHINE OR GROWL 1. Low fluid level. 1. Fill to proper level.
2. Pressure hose in contact with other
components.2. Reposition hose.
3. Internal pump noise. 3. Replace pump.
4. Air in fluid 4. Check for lekas, Evacuate air
from P/S system.
SUCKING AIR SOUND 1. Loose return line clamp. 1. Replace clamp.
2. O-ring missing or damaged on hose
fitting.2. Replace o-ring.
3. Low fluid level. 3. Fill to proper level.
4. Air leak between pump and reservoir. 4. Repair as necessary.
5. Reservoir cap not installed correctly. 5. Install reservoir cap correctly.
SCRUBBING OR
KNOCKING1. Wrong tire size. 1. Verify tire size.
19 - 2 STEERINGDR
STEERING (Continued)

BINDING AND STICKING
CONDITION POSSIBLE CAUSE CORRECTION
DIFFICULT TO TURN WHEEL
STICKS OR BINDS1. Low fluid level. 1. Fill to proper level.
2. Tire pressure. 2. Adjust tire pressure.
3. Steering components (ball
joints/tie rod ends).3 Inspect and repair as necessary.
4. Loose belt. 4. Adjust or replace.
5. Low pump pressure. 5. Pressure test and replace if
necessary.
6. Column shaft coupler binding. 6. Replace coupler.
7. Steering gear worn. 7. Replace gear.
8. Pump seized / Stuck valve 8. Replace pump.
INSUFFICIENT ASST. OR POOR RETURN TO CENTER
CONDITION POSSIBLE CAUSE CORRECTION
HARD TURNING OR MOMENTARY
INCREASE IN TURNING EFFORT1. Tire pressure. 1. Adjust tire pressure.
2. Low fluid level. 2. Fill to proper level.
3. Loose belt. 3. Adjust or replace.
4. Low pump pressure. 4. Pressure test and repair as
necessary.
5. Internal gear leak. 5. Replace gear.
STEERING WHEEL DOES NOT
WANT TO RETURN TO CENTER
POSITION1. Tire pressure. 1. Adjust tire pressure.
2. Wheel alignment. 2. Align front end.
3. Lack of lubrication. 3. Inspect and lubricate suspension
compnents.
4. High friction in steering gear. 4. Replace gear.
LOOSE STEERING AND VEHICLE LEAD
CONDITION POSSIBLE CAUSE CORRECTION
EXCESSIVE PLAY IN STEERING
WHEEL1. Worn or loose suspension or
steering components.1. Inspect and repair as necessary.
2. Worn or loose wheel bearings. 2. Inspect and repair or adjust
bearings.
3. Steering gear mounting. 3. Tighten gear mounting bolts to
specification.
4. Gear out of adjustment. 4. Replace gear.
5. Worn or loose steering coupler. 5. Inspect and replace as
necessary.
VEHICLE PULLS OR LEADS TO
ONE SIDE.1. Tire Pressure. 1. Adjust tire pressure.
2. Radial tire lead. 2. Rotate tires.
3. Brakes dragging. 3. Repair as necessary.
4. Wheel alignment. 4. Align front end.
DRSTEERING 19 - 3
STEERING (Continued)

(8) For columns without tilt remove the bracket to
gain access to the ignition switch mounting screws.
(Fig. 10)
(9) Disconnect the electrical connector at rear of
ignition switch (Fig. 11).
(10) Remove ignition switch mounting screw.
(11) Using a small screwdriver, push on locking
tab and remove switch from steering column.
INSTALLATION
The ignition key must be in the key cylinder for
cylinder removal. The key cylinder must be removed
first before installing ignition switch.
(1) Before installing ignition switch, rotate the slot
in the switch to the ON position.(2) Connect the electrical connector to rear of the
ignition switch. Make sure that locking tabs are fully
seated into wiring connector.
(3) Position switch to column and install the
mounting screw. Tighten screw to 3 N´m (26 in. lbs.).
(4) Install the tilt lever bracket mounting screws.
Tighten screws to 4.5 N´m (40 in. lbs.).
(5) If the column is non-tilt install the bracket.
Tighten screws to 4.5 N´m (40 in. lbs.) (Fig. 10)
(6) Position the wire retainer into the tilt lever
bracket.
(7) Reconnect the lower clockspring connectors.
(8) Install the key cylinder.
(9) Install steering column upper and lower
shrouds.
(10) Enable the airbag system. (Refer to 8 - ELEC-
TRICAL/RESTRAINTS/DRIVER AIRBAG - INSTAL-
LATION).
KEY-IN IGNITION SWITCH
DESCRIPTION
The key-in ignition switch is integral to the igni-
tion switch, which is mounted on the left side of the
steering column. It closes a path to ground for the
Central Timer Module (CTM) when the ignition key
is inserted in the ignition key cylinder and the driver
door ajar switch is closed (driver door is open). The
key-in ignition switch opens the ground path when
the key is removed from the ignition key cylinder.
The ground path is also opened when the driver door
ajar switch is open (driver door is closed).
The key-in ignition switch cannot be repaired and,
if faulty or damaged, the entire ignition switch must
be replaced, (Refer to 19 - STEERING/COLUMN/IG-
NITION SWITCH - REMOVAL).
DIAGNOSIS AND TESTING - IGNITION SWITCH
AND KEY LOCK CYLINDER
ELECTRICAL DIAGNOSIS
For ignition switch electrical schematics, refer to
Ignition Switch in the appropriate section of Electri-
cal Wiring Diagrams.
MECHANICAL DIAGNOSIS (KEY DIFFICULT TO
ROTATE)
(Refer to 19 - STEERING/COLUMN/IGNITION
SWITCH - DIAGNOSIS AND TESTING).
Fig. 10 IGNITION SWITCH WITHOUT TILT
1 - Ignition Switch Mounting Screws
2 - Non-Tilt Mounitng Bracket Screws
Fig. 11 IGNITION SWITCH
1 - Ignition Switch
2 - Ignition Switch Mounting Screws
DRCOLUMN 19 - 11
IGNITION SWITCH (Continued)

(2) Cycle the key from ACC to RUN and ensure
that the blocker does not stick or bind.
(3) Turn the key to the OFF position and ensure
that the shifter will not pull from the PARK position.
(4) Connect the over drive switch harness (if
equipped).
NOTE: Route and tie off harness to original loca-
tion.
(5) Connect the shift cable to the lever.
(6) Ensure the gear shift lever and transmission
are in the PARK position and snap the cable adjust
clip in place.
(7) Install a new brake light switch (Refer to 8 -
ELECTRICAL/LAMPS/LIGHTING - EXTERIOR/
BRAKE LAMP SWITCH - INSTALLATION).
(8) Install the SKIM and halo.
(9) Install the upper and lower column shroud.
(10) Install the column back into place and
tighten.
(11) Install the kneeblocker. (Refer to 23 - BODY/
INSTRUMENT PANEL/KNEE BLOCKER - INSTAL-
LATION).
UPPER STEERING COUPLING
REMOVAL
(1) Disconnect the negative battery cable.
NOTE: The steering column on vehicles with an
automatic transmission may not be equipped with
an internal locking shaft that allows the ignition key
cylinder to be locked with the key. Alternative meth-
ods of locking the steering wheel for service will
have to be used.(2) Lock the steering wheel with the tire in the
straight position.
(3) Remove and discard the lower pinch bolt.
(4) Lower the steering coupler shaft from the col-
umn.
(5) Remove the upper steering coupling shaft seal
by pushing in the four tags securing it to the panel
(Fig. 16).
(6) Remove and discard the lower coupler pinch
bolt from the lower steering coupling shaft (Fig. 17).
(7) Remove the upper steering coupling shaft from
the vehicle (Fig. 17).
INSTALLATION
(1) Install the upper steering coupling shaft to the
vehicle (Fig. 17).
Fig. 15 GEAR SHIFT LEVER SPRING
1 - BLOCKER TO INHIBIT LINK SLOT
2 - GEAR SHIFT LEVER
Fig. 16 RELEASE TANGS
1 - RELEASE TANGS (4)
2 - UPPER STEERING COUPLER SHAFT
Fig. 17 UPPER STEERING COUPLER SHAFT
1 - LOWER STEERING COUPLER
2 - RELEASE TANGS (4)
3 - UPPER STEERING COUPLER SHAFT
DRCOLUMN 19 - 13
GEAR SHIFT LEVER (Continued)