warning DODGE RAM 1500 1998 2.G Workshop Manual

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

WINDSHIELD
WARNING
WINDSHIELD SAFETY PRECAUTIONS
WARNING: DO NOT OPERATE THE VEHICLE
WITHIN 24 HOURS OF WINDSHIELD INSTALLATION.
IT TAKES AT LEAST 24 HOURS FOR URETHANE
ADHESIVE TO CURE. IF IT IS NOT CURED, THE
WINDSHIELD MAY NOT PERFORM PROPERLY IN
AN ACCIDENT.
²URETHANE ADHESIVES ARE APPLIED AS A
SYSTEM. USE GLASS CLEANER, GLASS PREP
SOLVENT, GLASS PRIMER, PVC (VINYL) PRIMER
AND PINCH WELD (FENCE) PRIMER PROVIDED BY
THE ADHESIVE MANUFACTURER. IF NOT, STRUC-
TURAL INTEGRITY COULD BE COMPROMISED.
²DAIMLERCHRYSLER DOES NOT RECOMMEND
GLASS ADHESIVE BY BRAND. TECHNICIANS
SHOULD REVIEW PRODUCT LABELS AND TECHNI-
CAL DATA SHEETS, AND USE ONLY ADHESIVES
THAT THEIR MANUFACTURES WARRANT WILL
RESTORE A VEHICLE TO THE REQUIREMENTS OF
FMVSS 212. TECHNICIANS SHOULD ALSO INSURE
THAT PRIMERS AND CLEANERS ARE COMPATIBLE
WITH THE PARTICULAR ADHESIVE USED.
²BE SURE TO REFER TO THE URETHANE MAN-
UFACTURER'S DIRECTIONS FOR CURING TIME
SPECIFICATIONS, AND DO NOT USE ADHESIVE
AFTER ITS EXPIRATION DATE.
²VAPORS THAT ARE EMITTED FROM THE URE-
THANE ADHESIVE OR PRIMER COULD CAUSE
PERSONAL INJURY. USE THEM IN A WELL-VENTI-
LATED AREA.
²SKIN CONTACT WITH URETHANE ADHESIVE
SHOULD BE AVOIDED. PERSONAL INJURY MAY
RESULT.
²ALWAYS WEAR EYE AND HAND PROTECTION
WHEN WORKING WITH GLASS.
CAUTION: Protect all painted and trimmed surfaces
from coming in contact with urethane or primers.
Be careful not to damage painted surfaces when
removing moldings or cutting urethane around
windshield.
REMOVAL
(1) Remove inside rear view mirror. (Refer to 23 -
BODY/INTERIOR/REAR VIEW MIRROR -
REMOVAL).
(2) Remove cowl grill. (Refer to 23 - BODY/EXTE-
RIOR/COWL GRILLE - REMOVAL).(3) Remove the a-pillar weatherstrip retainer.
(Refer to 23 - BODY/WEATHERSTRIP/SEALS/A-
PILLAR WEATHERSTRIP RETAINER - REMOVAL)
(4) Remove the a-pillar trim panels. (Refer to 23 -
BODY/INTERIOR/A-PILLAR TRIM - REMOVAL)
(5) Remove the headliner and from the inside of
the vehicle, cut the upper urethane bonding from
around windshield upper edge using a suitable sharp
cold knife (C-4849). A pneumatic cutting device can
be used but is not recommended. (Refer to 23 -
BODY/INTERIOR/HEADLINER - REMOVAL)
(6) From the outside of the vehicle, cut urethane
bonding from the remaining sides of the windshield
using a suitable sharp cold knife (C-4849). A pneu-
matic cutting device can be used but is not recom-
mended.
(7) Separate windshield from vehicle.
INSTALLATION
WARNING: Allow the urethane at least 24 hours to
cure before returning the vehicle to use.
CAUTION: Roll down the left and right front door
glass and open the rear glass slider (if available)
before installing windshield to avoid pressurizing
the passenger compartment if a door is slammed
before urethane is cured. Water leaks can result.
The windshield fence should be cleaned of most of
its old urethane bonding material. A small amount of
old urethane, approximately 1-2 mm in height,
should remain on the fence. Do not grind off or com-
pletely remove all old urethane from the fence, the
paint finish and bonding strength will be adversely
affected.
(1) Place replacement windshield into windshield
opening and position glass in the center of the open-
ing against the support spacers. Mark the outside
surface of the glass at the support spacers with a
grease pencil or pieces of masking tape and ink pen
to use as a reference for installation. Remove replace-
ment windshield from windshield opening (Fig. 5).
(2) Position the windshield inside up on a suitable
work surface with two padded, wood 10 cm by 10 cm
by 50 cm (4 in. by 4 in. by 20 in.) blocks, placed par-
allel 75 cm (2.5 ft.) apart (Fig. 6).
(3) Clean inside of windshield with MOPAR Glass
Cleaner and lint-free cloth.
(4) Apply clear glass primer 25 mm (1 in.) wide
around perimeter of windshield and wipe with a new
clean and dry lint- free cloth.
(5) Apply black-out primer onto the glass using the
windshield molding as a guide. The primer should be
15 mm (5/8 in.) wide on the top and sides of the glass
23 - 88 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)

Condition Possible Causes Correction
The low side pressure is too
low, and the high side
pressure is too high.1. Restricted refrigerant flow
through the refrigerant lines.1. See Liquid, Suction, and Discharge Line in this
group. Inspect the refrigerant lines for kinks, tight
bends or improper routing. Correct the routing or
replace the refrigerant line, if required.
2. Restricted refrigerant flow
through the fixed orifice tube.2. See A/C Orifice Tube in this group. Replace
the liquid line, if required.
3. Restricted refrigerant flow
through the condenser.3. See A/C Condenser in this group. Replace the
restricted condenser, if required.
DIAGNOSIS AND TESTING - HEATER
PERFORMANCE TEST
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).
Check the coolant level, drive belt tension, vacuum
line connections, radiator air flow and fan operation.
Start engine and allow to warm up to normal tem-
perature.
WARNING: DO NOT REMOVE RADIATOR CAP
WHEN ENGINE IS HOT, PERSONAL INJURY CAN
RESULT.
If vehicle has been run recently, wait 15 minutes
before removing cap. Place a rag over the cap andturn it to the first safety stop. Allow pressure to
escape through the overflow tube. When the system
stabilizes, remove the cap completely.
MAXIMUM HEATER OUTPUT: TEST AND ACTION
Engine coolant is provided to the heater system by
two heater hoses. With the engine idling at normal
operating temperature, set the temperature control
to maximum heat, the mode control to the floor posi-
tion, and the blower in the highest speed position.
Using a test thermometer, check the temperature of
the air being discharged from the floor outlets. Com-
pare the test thermometer reading to the Tempera-
ture Reference chart.
TEMPERATURE REFERENCE CHART
Ambient Air Temperature15.5É C
(60É F)21.1É C
(70É F)26.6É C
(80É F)32.2É C
(90É F)
Minimum Air Temperature at
Floor Outlet62.2É C
(144É F)63.8É C
(147É F)65.5É C
(150É F)67.2É C
(153É F)
Both of the heater hoses should be HOT to the
touch (coolant return hose should be slightly cooler
than the supply hose). If the coolant return hose is
much cooler than the supply hose, locate and repair
the engine coolant flow obstruction in the heater sys-
tem. If both heater hoses are cool to the touch,
inspect the engine cooling system (Refer to 7 -
COOLING - DIAGNOSIS AND TESTING).
OBSTRUCTED COOLANT FLOW Possible loca-
tions or causes of obstructed coolant flow are as fol-
lows:
²Pinched or kinked heater hoses.
²Improper heater hose routing.
²Plugged heater hoses or supply and return ports
at the cooling system connections.
²Plugged heater core.If proper coolant flow through the cooling system is
verified, and heater outlet air temperature is insuffi-
cient, a mechanical problem may exist.
MECHANICAL PROBLEMS Possible causes of
insufficient heat due to mechanical problems are as
follows:
²Obstructed cowl air intake.
²Obstructed heater system outlets.
²Blend door not functioning properly.
TEMPERATURE CONTROL
If the heater outlet air temperature cannot be
adjusted with the temperature control knob on the
A/C-heater control, the following could require ser-
vice:
²Blend door binding.
²Faulty blend door motor.
24 - 6 HEATING & AIR CONDITIONINGDR
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)

DIAGNOSIS AND TESTING - BLOWER MOTOR
RESISTOR BLOCK
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.
For circuit descriptions and diagrams, refer to the
appropriate wiring information. The wiring informa-
tion includes wiring diagrams, proper wire and con-
nector repair procedures, further details on wire
harness routing and retention, as well as pin-out and
location views for the various wire harness connec-
tors, splices and grounds.
(1) Disconnect and isolate the negative battery
cable.
(2) Disconnect the wire harness connector from the
blower motor resistor block.
(3) Check for continuity between each of the
blower motor switch input terminals of the resistor
and the resistor output terminal. In each case there
should be continuity. If OK, repair the wire harness
circuits between the blower motor switch and blower
motor resistor or blower motor as required. If not
OK, replace the faulty blower motor resistor block.
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.CAUTION: Stay clear of the blower motor resistor
block heat sink (Hot). Do not operate the blower
motor with the resistor block removed.
(1) Disconnect and isolate the negative battery
cable.
(2) Reach under the instrument panel near the
blower motor and disconnect the wire harness con-
nector from the blower motor resistor block.
(3) Remove the two screws that secure the blower
motor resistor block to the HVAC housing.
(4) Remove the resistor block from the HVAC
housing.
INSTALLATION
(1) Position the blower motor resistor block into
the HVAC housing.
(2) Install the two screws that secure the resistor
block to the HVAC housing. Tighten the screws to 2.2
N´m (20 in. lbs.).
(3) Connect the wire harness connector to the
resistor block.
(4) Reconnect the battery negative cable.
Fig. 17 Blower Motor Resistor Block
1 - SCREW (2)
2 - WIRE HARNESS CONNECTOR
3 - HVAC HOUSING
4 - BLOWER MOTOR RESISTOR BLOCK
5 - BLOWER MOTOR
DRCONTROLS 24 - 19
BLOWER MOTOR RESISTOR BLOCK (Continued)

BLOWER MOTOR SWITCH
DESCRIPTION
The blower motor is controlled by a rotary-type
blower motor switch, mounted in the A/C-heater con-
trol. The switch allows the selection of one of four
different blower motor speeds and includes an Off
position.
OPERATION
The blower motor switch provides a blower motor
ground path through the A/C-heater mode control
switch. The blower motor switch directs this ground
path through or around the blower motor resistor
wires, as required to achieve the selected blower
motor speed.
The blower motor switch cannot be repaired and, if
faulty or damaged, the entire A/C-heater control
must be replaced.
DIAGNOSIS AND TESTING - BLOWER MOTOR
SWITCH
For circuit descriptions and diagrams, refer to the
appropriate wiring information. The wiring informa-
tion includes wiring diagrams, proper wire and con-
nector repair procedures, further details on wire
harness routing and retention, as well as pin-out and
location views for the various wire harness connec-
tors, splices and grounds.
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) Check for battery voltage at the fuse in the
Power Distribution Center (PDC). 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 Off position.
Disconnect and isolate the battery negative cable.
Remove the A/C-heater control from the instrument
panel (Refer to 24 - HEATING & AIR CONDITION-
ING/CONTROLS/A/C HEATER CONTROL -
REMOVAL). Check for continuity between the
ground circuit cavity of the A/C-heater control wire
harness connector and a good ground. There should
be continuity. If OK, go to Step 3. If not OK, repair
the open circuit to ground as required.
(3) With the A/C-heater control wire harness con-
nector disconnected, place the A/C-heater mode con-
trol switch in any position except the Off position.
Check for continuity between the ground circuit ter-
minal and each of the blower motor driver circuit ter-
minals of the A/C-heater control as you move the
blower motor switch to each of the four speed posi-
tions. There should be continuity at each driver cir-
cuit terminal in only one blower motor switch speed
position. If OK, test and repair the blower driver cir-
cuits between the A/C-heater control connector and
the blower motor resistor as required. If not OK,
replace the faulty A/C-heater control.
DEFROST DOOR ACTUATOR
DESCRIPTION
The defrost door actuator is a reversible, 12-volt
Direct Current (DC), servo motor. The defrost door
actuator is located on the driver side end of the
HVAC housing, underneath the instrument panel
and is mechanically connected to the defroster door.
The defrost door actuator is interchangeable with
the actuators for the mode door, blend door(s) and
the recirculation door. Each actuator is contained
within an identical black molded plastic housing with
an integral wire connector 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 linkage that drives the proper door.
The defrost door actuator does not require mechani-
Fig. 18 A/C-Heater Control - Single Zone Shown,
Dual Zone Typical
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
24 - 20 CONTROLSDR

cal indexing to the defrost door, as it is electronically
calibrated by the heater-A/C control module. The
defrost door actuator cannot be adjusted or repaired
and, if damaged or faulty, it must be replaced.
OPERATION
The defrost door actuator is connected to the heat-
er-A/C control module through the vehicle electrical
system by a dedicated two-wire lead and connector
from the HVAC wire harness. The defrost door actua-
tor can move the defrost door in two directions.
When the heater-A/C control module pulls the volt-
age on one side of the motor connection high and the
other connection low, the defrost door will move in
one direction. When the module reverses the polarity
of the voltage to the motor, the defrost door moves in
the opposite direction. When the module makes the
voltage to both connections high or both connections
low, the defrost door stops and will not move. These
same motor connections also provide a feedback sig-
nal to the heater-A/C control module. This feedback
signal allows the module to monitor the operation
and relative positions of the defrost door actuator
and the defrost door. The heater-A/C control module
learns the defrost door stop positions during the cal-
ibration procedure and will store a Diagnostic Trou-
ble Code (DTC) for any problems it detects in the
defrost door actuator circuits. The defrost door actua-
tor can be diagnosed using a DRBIIItscan tool.
Refer to Body Diagnostic Procedures.
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 instrument panel from the vehicle
(Refer to 23 - BODY/INSTRUMENT PANEL/IN-
STRUMENT PANEL ASSEMBLY - REMOVAL).
(3) Disconnect the wire harness connector from the
defrost door actuator (Fig. 19).
(4) Remove the screws that secure the defrost door
actuator to the HVAC housing.(5) Remove the defrost door actuator from the
HVAC housing.
INSTALLATION
(1) Position the defrost door actuator into the
HVAC housing. If necessary, rotate the actuator
slightly to align the splines on the actuator output
sleeve with those on the defrost door linkage.
(2) Install and tighten the screws that secure the
defrost door actuator to the HVAC housing. Tighten
the screws to 2 N´m (17 in. lbs.).
(3) Connect the HVAC wire harness connector to
the defrost door actuator.
(4) Install the instrument panel (Refer to 23 -
BODY/INSTRUMENT PANEL/INSTRUMENT
PANEL ASSEMBLY - INSTALLATION).
(5) Reconnect the battery negative cable.
Fig. 19 HVAC Housing - Dual Zone Shown, Single
Zone Typical
1 - NUT
2 - PASSENGER BLEND DOOR ACTUATOR
3 - NUT
4 - INLET BAFFLE
5 - RECIRCULATION DOOR ACTUATOR
6 - RECIRCULATION DOOR
7 - DRIVER SIDE BLEND DOOR ACTUATOR
8 - HVAC HOUSING
9 - BOLT
10 - DEFROSTER DOOR ACTUATOR
11 - MODE DOOR ACTUATOR
DRCONTROLS 24 - 21
DEFROST DOOR ACTUATOR (Continued)

(2) Assemble the HVAC housing (Refer to 24 -
HEATING & AIR CONDITIONING/DISTRIBUTION/
HVAC HOUSING - ASSEMBLY).
(3) Connect the HVAC wire harness connector to
the evaporator temperature sensor.
(4) Install the HVAC housing (Refer to 24 - HEAT-
ING & AIR CONDITIONING/DISTRIBUTION/HVAC
HOUSING - INSTALLATION).
(5) Reconnect the battery negative cable.
MODE DOOR ACTUATOR
DESCRIPTION
The mode door actuator is a reversible 12-volt
Direct Current (DC) servo motor. The mode door
actuator is located on the HVAC housing, behind the
instrument panel and is mechanically connected to
the mode door.
The mode door actuator is interchangeable with
the actuators for the blend door(s), defrost door and
the recirculation door. Each actuator is contained
within an identical black molded plastic housing with
an integral wire connector 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 linkage that drives the proper door.
The mode door actuator does not require mechanical
indexing to the mode door linkage, as it is electroni-
cally calibrated by the heater-A/C control module.
The mode door actuator cannot be adjusted or
repaired and, if damaged or faulty, it must be
replaced.
OPERATION
The mode 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 mode door actuator can
move the mode door in two directions. When the A/C-
heater control pulls the voltage on one side of the
motor connection high and the other connection low,
the mode door will move in one direction. When the
A/C-heater control reverses the polarity of the volt-
age to the motor, the mode door moves in the oppo-
site direction. When the A/C-heater control makes
the voltage to both connections high or both connec-
tions low, the mode door stops and will not move.
These same motor connections also provide a feed-
back signal to the A/C-heater control. This feedback
signal allows the A/C-heater control to monitor the
operation and relative position of the mode door
actuator and the mode door. The A/C-heater control
learns the mode door stop positions during the cali-
bration procedure and will store a diagnostic troublecode (DTC) for any problems it detects in the mode
door actuator circuits.
The mode door actuator can be diagnosed using a
DRBIIItscan tool. Refer to Body Diagnostic Proce-
dures for more information. The mode door actuator
cannot be adjusted or repaired and, if damaged or
faulty, it 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.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the instrument panel from the vehicle
(Refer to 23 - BODY/INSTRUMENT PANEL/IN-
STRUMENT PANEL ASSEMBLY - REMOVAL).
(3) Disconnect the wire harness connector from the
mode door actuator (Fig. 22).
(4) Remove the screws that secure the mode door
actuator to the HVAC housing.
(5) Remove the mode door actuator from the HVAC
housing.
INSTALLATION
(1) Position the mode door actuator onto the HVAC
housing. If necessary, rotate the actuator slightly to
align the splines on the actuator output sleeve with
those on the mode door linkage.
(2) Install and tighten the screws that secure the
mode door actuator to the HVAC housing. Tighten
the screws to 2 N´m (17 in. lbs.).
(3) Connect the HVAC wire harness connector to
the mode door actuator.
(4) Install the instrument panel (Refer to 23 -
BODY/INSTRUMENT PANEL/INSTRUMENT
PANEL ASSEMBLY - INSTALLATION).
(5) Reconnect the battery negative cable.
DRCONTROLS 24 - 23
EVAPORATOR TEMPERATURE SENSOR (Continued)