Egr DODGE RAM 1500 1998 2.G Workshop Manual

²Panel repair for both flexible and rigid panels
are basically the same. The primary difference
between flexible panel repair and rigid panel repair
is in the adhesive materials used (Fig. 5).
²The technician should first decide what needs to
be done when working on any type of body panel.
One should determine if it is possible to return the
damage part to its original strength and appearance
without exceeding the value of the replacement part.
²When plastic repairs are required, it is recom-
mended that the part be left on the vehicle when
every possible. That will save time, and the panel
will remain stationary during the repair. Misalign-ment can cause stress in the repair areas and can
result in future failure.
VISUAL INSPECTION
Composite materials can mask the severity of an
accident. Adhesive bond lines, interior structure of
the doors, and steel structures need to be inspected
carefully to get a true damage assessment. Close
inspection may require partial removal of interior
trim or inner panels.
Identify the type of repair: Puncture or Crack -
Damage that has penetrated completely through the
panel. Damage is confined to one general area; a
panel section is not required. However, a backer
panel, open fiberglass tape, or matted material must
be bonded from behind (Fig. 7) (Fig. 6).
PANEL SURFACE PREPARATION
If a body panel has been punctured, cracked, or
crushed, the damaged area must be removed from
the panel to achieve a successful repair. All spider
web cracks leading away from a damaged area must
be stopped or removed. To stop a running crack in a
panel, drilla6mm(0.250 in.) hole at the end of the
crack farthest away from the damage. If spider web
cracks can not be stopped, the panel would require
replacement. The surfaces around the damaged area
Fig. 2 SOFTENED EDGES
1 - SOFTENED EDGES
2 - PANEL ADHESIVE
3 - BONDING STRIP
Fig. 3 PANEL REINFORCEMENT
1 - PANEL ADHESIVE
2 - REINFORCEMENT
Fig. 4 BEVELING ANGLE - 20 DEGREE
Fig. 5 FIBERGLASS TAPE
Fig. 6 DAMAGE COMPONENT
1 - PUNCTURE
DRBODY 23 - 7
BODY (Continued)

should be stripped of paint and freed from wax and
oil. Scuff surfaces around repair area with 360 grit
wet/dry sandpaper, or equivalent, to assure adhesion
of repair materials.
PATCHING PANELS
An panel that has extensive puncture type damage
can be repaired by cutting out the damaged material
(Fig. 7). Use a suitable reciprocating saw or cut off
wheel to remove the section of the panel that is dam-
aged. The piece cut out can be used as a template to
shape the new patch. It is not necessary to have
access to the back of the panel to install a patch.
Bevel edges of cutout at 20 degrees to expose a larger
bonding area on the outer side. This will allow for an
increased reinforcement areas.
PANEL PATCH FABRICATIONS
A patch can be fabricated from any rigid fiberglass
panel that has comparable contour with the repair
area. Lift gates and fenders can be used to supply
patch material. If existing material is not available
or compatible, a patch can be constructed with adhe-
sive and reinforcement mesh (dry wall tape). Perform
the following operation if required:
(1) Cover waxed paper or plastic with adhesive
backed nylon mesh (dry wall tape) larger than the
patch required (Fig. 8).(2) Tape waxed paper or plastic sheet with mesh to
a surface that has a compatible contour to the repair
area.
(3) Apply a liberal coat of adhesive over the rein-
forcement mesh (Fig. 8). If necessary apply a second
or third coat of adhesive and mesh after first coat
has cured. The thickness of the patch should be the
same as the repair area.
(4) After patch has cured, peel waxed paper or
plastic from the back of the patch.
(5) If desired, a thin film coat of adhesive can be
applied to the back of the patch to cover mesh for
added strength.
PANEL PATCH INSTALLATION
(1) Make a paper or cardboard pattern the size
and shape of the cutout hole in the panel.
(2) Trim 3 mm (0.125 in.) from edges of pattern so
patch will have a gap between connecting surfaces.
(3) Using the pattern as a guide, cut the patch to
size.
(4) Cut scrap pieces of patch material into 50 mm
(2 in.) squares to use as patch supports to sustain
the patch in the cutout.
(5) Drill 4 mm (0.160 in.) holes 13 mm (0.5 in.) in
from edge of cutout hole (Fig. 7).
(6) Drill 4 mm (0.160 in.) holes 13 mm (0.5 in.)
away from edge of patch across from holes drilled
around cutout.
Fig. 7 DAMAGED PANEL CUTOUT AND PATCH
1 - CUTOUT
2 - DAMAGED BODY PANEL
3-4MM(0.160 IN.) HOLES
4 - PATCH CUT TO SIZE
Fig. 8 FABRICATED PANEL
1 - STRUCTURAL ADHESIVE
2 - FIBERGLASS CLOTH OR FIBERGLASS MESH TAPE
3 - WIDTH OF V-GROOVE
4 - WAXED PAPER
23 - 8 BODYDR
BODY (Continued)

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

ber above the heating, ventilation and air condition-
ing (HVAC) housing. On models equipped with air
conditioning, the air passes through the evaporator
coil. Air flow can be directed either through or
around the heater core. This is done by adjusting the
blend door with the temperature control knob on the
A/C-heater control located the instrument panel. The
air flow can then be directed from the panel, floor
and defrost outlets in various combinations using the
mode control knob located on the A/C-heater control.
Air flow velocity can be adjusted with the blower
speed selector located on the A/C-heater control.
NOTE: It is important to keep the air intake opening
clear of debris. Leaf particles and other debris that
is small enough to pass through the cowl opening
screen can accumulate within the HVAC housing.
The closed, warm, damp and dark environment cre-
ated within the housing is ideal for the growth of
certain molds, mildews and other fungi. Any accu-mulation of decaying plant matter provides an addi-
tional food source for fungal spores, which enter
the housing with the fresh intake-air. Excess debris,
as well as objectionable odors created by decaying
plant matter and growing fungi can be discharged
into the passenger compartment during heater-A/C
operation if the air intake opening is not kept clear
of debris.
The heater and air conditioning systems are blend-
air type systems. In a blend-air system, a blend door
controls the amount of unconditioned air (or cooled
air from the evaporator on models with air condition-
ing) that is allowed to flow through, or around, the
heater core. A temperature control knob determines
the discharge air temperature by actuating an elec-
tric motor, which operates the blend door. This allows
an almost immediate control of the output air tem-
perature of the system.
On all models, the outside air intake can be shut
off by selecting the Recirculation Mode with the
mode control knob. This will operate a electric actu-
ated recirculation air door that closes off the outside
fresh air intake and recirculates the air that is
already inside the vehicle.
The air conditioning compressor can be engaged in
any mode by pressing the snowflake, A/C on/off but-
ton. It can also be engaged by placing the mode con-
trol in the mix to defrost positions. This will remove
heat and humidity from the air before it is directed
through or around the heater core. The mode control
knob on the A/C-heater control is used to also direct
the conditioned air to the selected system outlets.
The mode control switch uses an electric motor to
control the mode doors.
The defroster outlet receives airflow from the
HVAC housing through the molded plastic defroster
duct, which connects to the HVAC housing defroster
outlet. The airflow from the defroster outlets is
directed by fixed vanes in the defroster outlet grilles
and cannot be adjusted. The defroster outlet grilles
are integral to the instrument panel top cover.
The side window demister outlets receive airflow
from the HVAC housing through the molded plastic
defroster duct and two molded plastic demister ducts.
The airflow from the side window demister outlets is
directed by fixed vanes in the demister outlet grilles
and cannot be adjusted. The side window demister
outlet grilles are integral to the instrument panel.
The demisters direct air from the HVAC housing
through the outlets located on the top corners of the
instrument panel. The demisters operate when the
mode control knob is positioned in the floor-defrost
and defrost-only settings. Some air may be noticeable
from the demister outlets when the mode control is
in the bi-level to floor positions.
Fig. 1 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
24 - 2 HEATING & AIR CONDITIONINGDR
HEATING & AIR CONDITIONING (Continued)

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)

spikes and electromagnetic interference that can be
generated as the electromagnetic field of the relay
coil collapses.
The A/C compressor clutch relay terminals are con-
nected to the vehicle electrical system through a
receptacle in the integrated power module (IPM). The
inputs and outputs of the A/C compressor clutch
relay include:
²The common feed terminal (30) receives a bat-
tery current input from a fuse in the IPM through a
fused B(+) circuit at all times.
²The coil ground terminal (86) receives a ground
input from the PCM/ECM through the A/C compres-
sor clutch relay control circuit only when the PCM/
ECM electronically pulls the control circuit to
ground.
²The coil battery terminal (85) receives a battery
current input from PTC 1 in the IPM through a
fused ignition switch output (run) circuit only when
the ignition switch is in the On position.
²The normally open terminal (87) provides a bat-
tery current output to the compressor clutch coil
through the A/C compressor clutch relay output cir-
cuit only when the A/C compressor clutch relay coil is
energized.
²The normally closed terminal (87A) is not con-
nected to any circuit in this application, but provides
a battery current output only when the A/C compres-
sor clutch relay coil is de-energized.
Refer to the appropriate wiring information for
diagnosis and testing of the micro-relay and for com-
plete HVAC wiring diagrams.
REMOVAL
(1) Disconnect and isolate the negative battery
cable.
(2) Remove the cover from the integrated power
module (IPM) (Fig. 11).
(3) Refer to the fuse and relay layout label on the
IPM cover for compressor clutch relay identification
and location.
(4) Remove the A/C compressor clutch relay from
the IPM.
INSTALLATION
(1) See the fuse and relay layout label affixed to
the underside of the IPM cover for A/C compressor
clutch relay location.
(2) Position the A/C compressor clutch relay in the
proper receptacle in the IPM.
(3) Align the A/C compressor clutch relay termi-
nals with the terminal cavities in the IPM receptacle.
(4) Push down firmly on the A/C compressor clutch
relay until the terminals are fully seated in the ter-
minal cavities in the IPM receptacle.
(5) Install the cover onto the IPM.(6) Reconnect the negative battery cable.
A/C HEATER CONTROL
DESCRIPTION
The heater and air conditioning systems use elec-
trical controls. These controls provide the vehicle
operator with a number of setting options to help
control the climate and comfort within the vehicle.
The A/C-heater control for the Single Zone system
(Fig. 12) or Dual Zone system (Fig. 13) is located to
the right of the instrument cluster on the instrument
panel.
The Single Zone control panel contains a rotary-
type temperature control switch, a rotary-type mode
control switch and a rotary-type blower motor speed
switch. The A/C-heater control also has a push but-
ton to activate the optional heated side view mirror
defroster elements and to turn the A/C on.
The Dual Zone control panel contains a pair of slid-
er-type temperature control switches, a rotary-type
mode control switch and a rotary-type blower motor
speed switch. The control also has buttons to activate
the optional heated sideview mirror defroster ele-
ments, turn the A/C on and set the system to Max
A/C.
The A/C-heater control panel cannot be repaired. If
faulty or damaged, the entire unit must be replaced.
Fig. 11 Integrated Power Module (IPM)
1 - BATTERY
2 - INTEGRATED POWER MODULE (IPM)
24 - 14 CONTROLSDR
A/C COMPRESSOR CLUTCH RELAY (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)

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

(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)

RECIRCULATION DOOR
ACTUATOR
DESCRIPTION
The recirculation door actuator is a reversible
12-volt Direct Current (DC) servo motor. The single
recirculation door actuator is located on the passen-
ger side end of the HVAC housing, on the top of the
air inlet housing. The recirculation door actuator is
mechanically connected to the recirculation air door.
The recirculation door actuator is interchangeable
with the actuators for the blend door(s), defrost door
and the mode 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 air inlet housing. Each actuator also has an
identical output shaft with splines that connects it tothe linkage that drives the proper door. The recircu-
lation door actuator does not require mechanical
indexing to the recirculation door linkage, as it is
electronically calibrated by the heater-A/C control
module. The recirculation door actuator cannot be
adjusted or repaired and, if damaged or faulty, it
must be replaced.
OPERATION
The recirculation door actuator is connected to the
heater-A/C control module through the vehicle elec-
trical system by a dedicated two-wire lead and con-
nector of the HVAC wire harness. The recirculation
door actuator can move the recirculation door in two
directions. When the heater-A/C control module pulls
the voltage on one side of the motor connection high
and the other connection low, the recirculation air
door will move in one direction. When the module
reverses the polarity of the voltage to the motor, the
recirculation air door moves in the opposite direction.
When the module makes the voltage to both connec-
tions high or both connections low, the recirculation
air door stops and will not move. These same motor
connections also provide a feedback signal to the
heater-A/C control module. This feedback signal
allows the module to monitor the operation and rela-
tive position of the recirculation door actuator and
the recirculation air door. The heater-A/C control
module learns the recirculation air door stop posi-
tions during the calibration procedure and will store
a Diagnostic Trouble Code (DTC) for any problems it
detects in the recirculation door actuator circuits.
The recirculation door actuator can be diagnosed
using a DRBIIItscan tool. Refer to Body Diagnostic
Procedures for more information. The recirculation
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.
Fig. 22 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
24 - 24 CONTROLSDR
MODE DOOR ACTUATOR (Continued)