1998 DODGE RAM 1500 ABS

(2) Install the shifter knob and nut and tighten to
27 N´m (20 ft. lbs.).
(3) Position the insert and seat into the knob fully.
A-PILLAR TRIM/GRAB HANDLE
REMOVAL
(1) Open the trim plugs and remove the bolts. (Fig.
3)
(2) Remove the a-pillar trim/grab handle from the
a-pillar.
INSTALLATION
(1) Position the bottom a-pillar locating tabs and
install the a-pillar trim.
(2) Install the bolts and tighten to 6 N´m (55 in.
lbs.).
(3) Close the trim plugs.
B-PILLAR LOWER TRIM
REMOVAL
(1) Remove the upper b-pillar trim. (Refer to 23 -
BODY/INTERIOR/B-PILLAR UPPER TRIM -
REMOVAL)
(2) Remove the cowl trim. (Refer to 23 - BODY/IN-
TERIOR/COWL TRIM - REMOVAL)
STANDARD CAB
(1) Remove the shoulder belt anchor bolt.
(2) Using a trim stick C-4755 or equivalent,
remove the lower b-pillar trim. (Fig. 4)
QUAD CAB
(1) Remove the rear door sill trim. (Refer to 23 -
BODY/INTERIOR/REAR DOOR SILL TRIM COVER
- REMOVAL)
(2) Using a trim stick C-4755 or equivalent,
remove the lower b-pillar trim.
Fig. 1 SHIFTER BOOT
1 - CONSOLE
2 - SHIFTER KNOB
3 - SHIFTER BOOT
Fig. 2 SHIFTER KNOB
1 - SHIFTER KNOB
2 - INSERT
3 - NUT
Fig. 3 A-PILLAR TRIM/GRAB HANDLE
1 - A-PILLAR
2 - A-PILLAR TRIM
3 - TRIM PLUG
4 - BOLTS (2)
DRINTERIOR 23 - 63
4WD FLOOR SHIFT BOOT (Continued)

INSTALLATION
(1) Snap the visor support into the sheet metal
and seat the release clip fully.
BODY VENT
REMOVAL
(1) Remove the cab back panel trim. (Refer to 23 -
BODY/INTERIOR/REAR CAB BACK PANEL TRIM -
REMOVAL)
(2) While holding the vent, press the tabs to
release the vent into the cab back panel. (Fig. 20)
(3) Twist the vent and remove through the vent
hole.
INSTALLATION
(1) Position the vent into the vent hole in the cab
back panel.
(2) Twist the vent and pull it into the hole frame
and seat the tabs fully.
(3) Install the cab back panel trim. (Refer to 23 -
BODY/INTERIOR/REAR CAB BACK PANEL TRIM -
INSTALLATION)
REAR DOOR SILL TRIM COVER
REMOVAL
(1) Using a trim stick C-4755 or equivalent, pry up
the sill trim and remove. (Fig. 21)
INSTALLATION
(1) Position the sill trim and seat the attachment
clips fully.
LOAD FLOOR
REMOVAL
(1) Fold the rear seat cushion up.
(2) Remove the rear nuts in each corner. (Fig. 22)
(3) Fold the load floor up, remove the front bolts
and remove the tray. (Fig. 23)
Fig. 20 BODY VENT
1 - RETAINER TABS
2 - BODY VENT
3 - CAB BACK PANEL
Fig. 21 REAR DOOR SILL TRIM
1 - SILL TRIM
2 - REAR DOOR SILL
Fig. 22 REAR LOAD FLOOR - REAR FASTENERS
1 - REAR SEAT CUSHION
2 - NUTS (2)
3 - STOWAGE TRAY
DRINTERIOR 23 - 71
SUN VISOR SUPPORT (Continued)

INSTALLATION
NOTE: Do not reuse the seat fasteners, always
replace with new ones.
(1) Install the seat back onto the storage bin/cush-
ion and install new hinge bolts.
(2) Tighten the hinge to storage bin/cushion bolts
to 25 N´m (18 ft. lbs.).
(3) Connect the storage bin/cushion cover j-straps.
(4) Install the center seat. (Refer to 23 - BODY/
SEATS/SEAT - CENTER - INSTALLATION)
CENTER SEAT BACK INERTIA
HINGE COVER
REMOVAL
NOTE: Free pivot hinge cover is removed with the
free pivot hinge. (Refer to 23 - BODY/SEATS/CEN-
TER SEAT BACK HINGE - REMOVAL)
(1) For the inertia hinge cover disconnect the zip
strip. (Fig. 5)
(2) Position aside the storage bin/cushion cover.
(3) Remove the pivot bolt.
(4) Open the hinge cover at the bottom and remove
the hinge cover. (Fig. 6)
INSTALLATION
NOTE: Free pivot hinge cover is installed with the
free pivot hinge. (Refer to 23 - BODY/SEATS/CEN-
TER SEAT BACK HINGE - INSTALLATION)
Fig. 4 CENTER SEAT BACK HINGES
1 - STORAGE BIN/CUSHION COVERING
2 - SEAT BACK HINGE BOLTS (4)
3 - STORAGE BIN/CUSHION FRAME
Fig. 5 HINGE COVER
1 - SEAT BACK COVER ZIP STRIP
2 - CENTER SEAT BACK
3 - HINGE COVER
4 - STORAGE BIN COVER
5 - PIVOT BOLT
Fig. 6 HINGE COVER REMOVAL
1 - HINGE COVER
2 - HINGE
3 - HINGE COVER TABS
4 - CENTER SEAT BACK
5 - STORAGE BIN/CUSHION
DRSEATS 23 - 77
CENTER ARMREST / SEAT BACK (Continued)

(1) Position the hinge cover over the hinge and
close over the lock tabs.
(2) Install the pivot bolt and tighten to 10 N´m (89
in. lbs.).
(3) Reposition the storage bin/cushion cover.
(4) Connect the zip strip.
CENTER SEAT BACK HINGE
REMOVAL
NOTE: Do not reuse the seat fasteners, always
replace with new ones.
(1) Remove the seat back. (Refer to 23 - BODY/
SEATS/CENTER ARMREST / SEAT BACK -
REMOVAL)
Free Pivot Hinge/Cover
(1) Disconnect the storage bin/cushion cover j-strap
and position aside.
(2) Remove and discard the pivot bolt. (Fig. 7)
(3) Remove the hinge spacer. (Fig. 8)
(4) Open the hinge cover flap and remove the wire
harness, if equipped. (Fig. 9)
(5) Remove the cover from the hinge.
Fig. 7 PIVOT HINGE/COVER
1 - PIVOT BOLT
2 - HINGE COVER
3 - STORAGE BIN COVER
4 - 12V POWER SUPPLY HARNESS
5 - HINGE BOLTS (2)
6 - HINGE
Fig. 8 PIVOT HINGE SPACER
1 - HINGE COVER
2 - SPACER
3-STOPPIN
Fig. 9 PIVOT HINGE COVER
1 - HINGE COVER FLAP
2-STOPPIN
3 - HINGE COVER
4 - HINGE
5 - 12V POWER SUPPLY HARNESS
23 - 78 SEATSDR
CENTER SEAT BACK INERTIA HINGE COVER (Continued)

STATIONARY GLASS
TABLE OF CONTENTS
page page
BACKLITE
REMOVAL.............................86
INSTALLATION.........................86
BACKLITE VENT GLASS
REMOVAL.............................87
INSTALLATION.........................87WINDSHIELD
WARNING
WINDSHIELD SAFETY PRECAUTIONS.....88
REMOVAL.............................88
INSTALLATION.........................88
BACKLITE
REMOVAL
It is difficult to salvage the backlite during the
removal operation. The backlite is part of the struc-
tural support for the roof. The urethane bonding
used to secure the glass to the fence is difficult to cut
or clean from any surface. Since the molding is set in
urethane, it is unlikely it would be salvaged. Before
removing the backlite, check the availability from the
parts supplier.
The backlite is attached to the window frame with
urethane adhesive. The urethane adhesive is applied
cold and seals the surface area between the window
opening and the glass. The primer adheres the ure-
thane adhesive to the backlite.
(1) Roll down door glass.
(2) Remove headliner. (Refer to 23 - BODY/INTE-
RIOR/HEADLINER - REMOVAL).
(3) On standard cab models remove the upper
b-pillar trim. (Refer to 23 - BODY/INTERIOR/B-PIL-
LAR UPPER TRIM - REMOVAL)
(4) On quad cab models remove the upper c-pillar
trim. (Refer to 23 - BODY/INTERIOR/C-PILLAR
UPPER TRIM - REMOVAL)
(5) Bend backlite retaining tabs (Fig. 1) inward
against glass.
(6) Disconnect the rear window defogger electrical
connector, if equipped.
(7) Using a suitable pneumatic knife from inside
the vehicle, cut urethane holding backlite frame to
opening fence.
(8) Separate glass from vehicle.
INSTALLATION
(1) Clean urethane adhesive from around backlite
opening fence.
(2) If necessary, apply black-out primer to outer
edge of replacement backlite frame.(3) If black-out primer was pre-applied on backlite,
clean bonding surface with Isopropyl alcohol and
clean lint free cloth. Allow 3 minutes for drying time.
(4) Apply black-out primer to backlite opening
fence.
(5) Apply a 13 mm (0.5 in.) bead of urethane
around the perimeter of the window frame bonding
surface (Fig. 2).
(6) Set glass on lower fence and move glass for-
ward into opening (Fig. 3).
(7) Firmly push glass against rear window glass
opening fence.
(8) Bend tabs around edges of backlite opening
fence to retain glass.
(9) Clean excess urethane from exterior with
MOPARt, Super Clean or equivalent.
(10) Allow urethane to cure at least 24 hours (full
cure is 72 hours).
(11) Water test to verify repair before returning
vehicle to service.
(12) Connect the rear window defogger electrical
connector, if equipped.
Fig. 1 Backlite Tabs
1 - BACKLITE
2-TAB
23 - 86 STATIONARY GLASSDR

The panel outlets receive airflow from the HVAC
housing through a molded plastic main panel duct,
center panel duct and two end panel ducts. The two
end panel ducts direct airflow to the left and right
instrument panel outlets, while the center panel duct
directs airflow to the two center panel outlets. Each
of these outlets can be individually adjusted to direct
the flow of air.
The floor outlets receive airflow from the HVAC
housing through the floor distribution duct. The front
floor outlets are integral to the molded plastic floor
distribution duct, which is secured to the bottom of
the housing. The floor outlets cannot be adjusted.
The air conditioner for all models is designed for
the use of non-CFC, R-134a refrigerant. The air con-
ditioning system has an evaporator to cool and dehu-
midify the incoming air prior to blending it with the
heated air. This air conditioning system uses a fixed
orifice tube in the liquid line near the condenser out-
let tube to meter refrigerant flow to the evaporator
coil. To maintain minimum evaporator temperature
and prevent evaporator freezing, a evaporator tem-
perature sensor is used. The JTEC control module is
programmed to respond to the evaporator tempera-
ture sensor input by cycling the air conditioning com-
pressor clutch as necessary to optimize air
conditioning system performance and to protect the
system from evaporator freezing.
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - A/C
PERFORMANCE
The air conditioning system is designed to remove
heat and humidity from the air entering the passen-
ger compartment. The evaporator, located in the
HVAC housing, is cooled to temperatures near the
freezing point. As warm damp air passes over the
fins in the evaporator, moisture in the air condenses
to water, dehumidifying the air. Condensation on the
evaporator fins reduces the evaporators ability to
absorb heat. During periods of high heat and humid-
ity, an air conditioning system will be less effective.
With the instrument control set to Recirculation
mode, only air from the passenger compartment
passes through the evaporator. As the passenger com-
partment air dehumidifies, A/C performance levels
rise.
Humidity has an important bearing on the temper-
ature of the air delivered to the interior of the vehi-
cle. It is important to understand the effect that
humidity has on the performance of the air condition-
ing system. When humidity is high, the evaporator
has to perform a double duty. It must lower the air
temperature, and it must lower the temperature ofthe moisture in the air that condenses on the evapo-
rator fins. Condensing the moisture in the air trans-
fers heat energy into the evaporator fins and tubing.
This reduces the amount of heat the evaporator can
absorb from the air. High humidity greatly reduces
the ability of the evaporator to lower the temperature
of the air.
However, evaporator capacity used to reduce the
amount of moisture in the air is not wasted. Wring-
ing some of the moisture out of the air entering the
vehicle adds to the comfort of the passengers.
Although, an owner may expect too much from their
air conditioning system on humid days. A perfor-
mance test is the best way to determine whether the
system is performing up to standard. This test also
provides valuable clues as to the possible cause of
trouble with the air conditioning system.
PERFORMANCE TEST PROCEDURE
Review Safety Warnings and Cautions before per-
forming this procedure (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING - WARNING) and
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - CAUTION). Air temperature in test
room and on vehicle must be 21É C (70É F) minimum
for this test.
NOTE: When connecting the service equipment
coupling to the line fitting, verify that the valve of
the coupling is fully closed. This will reduce the
amount of effort required to make the connection.
(1) Connect a tachometer and a manifold gauge set
or A/C recycling/charging station.
(2) Set the A/C-heater mode control in the Recircu-
lation Mode position, the temperature control knob in
the full cool position, and the blower motor switch to
the highest speed position.
(3) Start the engine and hold at 1,000 rpm with
the A/C compressor clutch engaged.
(4) The engine should be warmed up to operating
temperature with the doors closed and windows
open.
(5) Insert a thermometer in the driver side center
panel A/C-heater outlet and operate the engine for
five minutes.
(6) The compressor clutch may cycle, depending
upon the ambient temperature and humidity.
(7) With the compressor clutch engaged, record the
discharge air temperature and the compressor dis-
charge pressure.
(8) If the discharge air temperature fails to meet
the specifications in the A/C Performance Tempera-
ture chart, refer to the Pressure Diagnosis chart.
DRHEATING & AIR CONDITIONING 24 - 3
HEATING & AIR CONDITIONING (Continued)

The illumination lamps are available for service
replacement.
REMOVAL
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, 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 AN ACCIDENTAL
AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the center bezel from the instrument
panel (Refer to 23 - BODY/INSTRUMENT PANEL/
INSTRUMENT PANEL CENTER BEZEL -
REMOVAL).
(3) Remove the screws that secure the A/C-heater
control to the instrument panel (Fig. 14).
INSTALLATION
(1) Position the A/C-heater control onto the instru-
ment panel center bezel and install the retaining
screws. Tighten the screws to 2.2 N´m (20 in. lbs.).
(2) Install the instrument panel center bezel (Refer
to 23 - BODY/INSTRUMENT PANEL/INSTRUMENT
PANEL CENTER BEZEL - INSTALLATION).
(3) Reconnect the battery negative cable.
A/C PRESSURE TRANSDUCER
DESCRIPTION
The A/C pressure transducer is a switch that is
installed on a fitting located on the refrigerant dis-
charge line between the compressor and the con-
denser in the front corner of the engine
compartment. An internally threaded hex fitting on
the transducer connects it to the externally threaded
Schrader-type fitting on the discharge line. A rubber
O-ring seals the connection between the transducer
and the discharge line fitting. Three terminals within
a molded plastic connector receptacle on the top of
the transducer connect it to the vehicle electrical sys-
tem through a wire lead and connector of the head-
lamp and dash wire harness.
Fig. 12 Single Zone HVAC Control
1 - MOUNTING TAB (4)
2 - A/C BUTTON
3 - SIDEVIEW MIRROR DEFROSTER BUTTON (IF EQUIPED)
4 - MODE CONTROL SWITCH
5 - TEMPERATURE CONTROL SWITCH
6 - BLOWER MOTOR SWITCH
Fig. 13 Dual Zone A/C Control
1 - A/C BUTTON
2 - MAX. A/C BUTTON
3 - SIDEVIEW MIRROR DEFROSTER BUTTON (IF EQUIPED)
4 - MOUNTING TABS (4)
5 - DRIVERSIDE TEMPERATURE CONTROL
6 - PASSENGERSIDE TEMPERATURE CONTROL
7 - MODE CONTROL SWITCH
8 - BLOWER MOTOR SWITCH
Fig. 14 A/C-Heater Control - Typical, Rear View
1 - MOUNTING TAB (4)
2 - SCREW (4)
3 - A/C-HEATER CONTROL ELECTRICAL CONNECTOR
4 - HEATED SIDEVIEW MIRROR ELECTRICAL CONNECTOR
5 - A/C-HEATER CONTROL
DRCONTROLS 24 - 15
A/C HEATER CONTROL (Continued)

(4) Reconnect the battery negative cable.
BLEND DOOR ACTUATOR
DESCRIPTION
The blend door actuators are reversible, 12-volt
Direct Current (DC), servo motors. Models with the
single zone heater and air conditioner system have a
single blend door, which is controlled by a single
blend door actuator. Models with the optional dual
zone front heater and air conditioner system have
dual blend doors, which are controlled by two blend
door actuators. The single zone blend door actuator is
located on the driver side end of the HVAC housing,
close to the dash panel. In the dual zone system, the
same blend door actuator used for the single zone
system becomes the driver side blend door actuator,
and is mechanically connected to only the driver side
blend door. In the dual zone system, a second sepa-
rate blend door actuator is also located on the top of
the HVAC housing and is mechanically connected to
only the passenger side blend door.
The blend door actuators are interchangeable with
each other, as well as with the actuators for the
mode door, defrost door and the recirculation door.
Each actuator is contained within an identical blackmolded plastic housing with an integral wire connec-
tor receptacle. Integral mounting tabs allow the
actuator to be secured with three screws to the
HVAC housing. Each actuator also has an identical
output shaft with splines that connects it to the link-
age that drives the proper door. The blend door
actuators do not require mechanical indexing to the
blend door linkage, as they are electronically cali-
brated by the heater-A/C control module. The blend
door actuators cannot be adjusted or repaired and, if
damaged or faulty, they must be replaced.
OPERATION
Each blend door actuator is connected to the A/C-
heater control through the vehicle electrical system by a
dedicated two-wire lead and connector from the HVAC
wire harness. The blend door actuator can move the
blend-air door in two directions. When the A/C-heater
control pulls the voltage on one side of the motor con-
nection high and the other connection low, the blend-air
door will move in one direction. When the A/C-heater
control reverses the polarity of the voltage to the motor,
the blend-air door moves in the opposite direction.
When the A/C-heater control makes the voltage to both
connections high or both connections low, the blend-air
door stops and will not move. The motor connections
also provide a feedback signal to the A/C-heater control.
This feedback signal allows the A/C-heater control to
monitor the operation and relative positions of the blend
door actuator and the blend-air door. The A/C-heater
control learns the blend door stop positions during the
calibration procedure and will store a diagnostic trouble
code (DTC) for any problems it detects in the blend door
actuator circuits.
The blend door actuator can be diagnosed using a
DRBIIItscan tool. Refer to Body Diagnostic Proce-
dures for more information. The blend door actuators
cannot be adjusted or repaired and, if damaged or
faulty, they must be replaced.
REMOVAL
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, 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.
Fig. 15 A/C Pressure Transducer - 3.7L Shown
1 - NUT
2 - FRONT UPPER CROSSMEMBER
3 - A/C CONDENSER
4 - NUT (2)
5 - SUCTION LINE
6 - A/C COMPRESSOR
7 - A/C PRESSURE TRANSDUCER
8 - WIRE HARNESS CONNECTOR
9 - A/C DISCHARGE LINE
DRCONTROLS 24 - 17
A/C PRESSURE TRANSDUCER (Continued)