opening at the base of the windshield. Then it goes
into the plenum chamber above the HVAC unit hous-
ing and passes through the evaporator. At this point
airflow can be directed either through or around the
heater core.

DESCRIPTION - HVAC FORCED
RECIRCULATION

The Body Control Module (BCM) receives a Pro-

grammable Communications Interface (PCI) bus mes-
sage from the Powertrain Control Module (PCM)
with the feedback from the A/C Pressure Transducer.
The BCM will force the system into the Recirculation
mode, reducing the A/C refrigerant pressure under
these extreme conditions. The reduced operating
pressure offers improved A/C system performance
and reduced wear on A/C components.

OPERATION - HVAC SYSTEM AIRFLOW

Airflow temperature can be adjusted by the blend

door with the TEMP control on the a/c heater control.
After the air passes the blend door, the air flow is
then directed from the PANEL, BI-LEVEL (panel
and floor), and FLOOR-DEFROST outlets. Air flow
velocity can be adjusted with the blower speed selec-
tor switch on the a/c heater control.

Ambient air intake can be shut off by closing the

recirculation door. This will recirculate the air that is
already inside the vehicle. See owners manual for
recirculation operation.

BLOWER MOTOR

DESCRIPTION

The blower motor and blower wheel are located in

the passenger side end of the HVAC housing, below
the glove box module. The blower motor controls the
velocity of the air flowing through the HVAC housing
by spinning a squirrel cage-type blower wheel within
the housing at the selected speed. The blower motor
and blower wheel can be serviced from the passenger
compartment side of the housing.

OPERATION

The blower motor will only operate when the igni-

tion switch is in the On position, and the a/c heater
mode control switch is in any position, except off. The
blower motor circuit is protected by a fuse in the
junction block. On models with the standard manual
temperature control system, the blower motor speed
is controlled by regulating the battery feed through
the blower motor switch and the blower motor resis-
tor. On models with Automatic Temperature Control
(ATC) system, the blower motor speed is controlled
by using a linear blower controller with a pulse
width modulation input. The blower motor power
module adjusts the battery feed voltage to the blower
motor, based upon an input from the blower motor
switch, through the ATC control module. Pulse width
modulation of blower power allows the blower to
operate at any speed from stationary, to full speed.

The blower motor and blower motor wheel cannot

be repaired, and if faulty or damaged, they must be
replaced. The blower motor and blower wheel are not
serviced separately and must be replaced as an
assembly.

DISTRIBUTION

24 - 23

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) Open the hood and disconnect the negative bat-

tery cable remote terminal from the remote battery
post(Refer to 8 - ELECTRICAL/BATTERY SYSTEM/
CABLES - REMOVAL).

(2) Remove the lower right under panel duct.
(3) Remove the blower motor connector from the

blower motor resistor block/power module.

(4) Squeeze the blower motor wiring grommet and

push the grommet through the blower motor housing
cover.

(5) Remove the blower motor housing cover.
(6) Remove the blower motor retaining screws.
(7) Lower the blower motor from housing.

INSTALLATION

(1) Install the blower motor in the HVAC housing

and tighten the mounting screws to 2.2 N·m (20 in.
lbs.).

(2) Install the blower motor housing cover.
(3) Position the blower motor wiring grommet in

the blower motor housing cover.

(4) Connect the blower motor harness connector to

the blower motor resistor block/power module.

(5) Install the lower right under panel duct.
(6) Connect the negative battery cable remote ter-

minal to the remote battery post(Refer to 8 - ELEC-
TRICAL/BATTERY

SYSTEM/CABLES

INSTALLATION).

HVAC HOUSING

REMOVAL

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.

WARNING: REVIEW THE WARNINGS IN THE FRONT
OF PLUMBING BEFORE PERFORMING THE FOL-
LOWING OPERATION. (Refer to 24 - HEATING & AIR
CONDITIONING/PLUMBING - WARNING)

(1) Open the hood and disconnect the negative bat-

tery cable remote terminal from the remote battery
post(Refer to 8 - ELECTRICAL/BATTERY SYSTEM/
CABLES - REMOVAL).

(2) Remove the instrument panel from vehicle(Re-

fer to 23 - BODY/INSTRUMENT PANEL/INSTRU-
MENT PANEL ASSEMBLY - REMOVAL).

(3) Recover the refrigerant from the system. (Refer

to 24 - HEATING & AIR CONDITIONING/PLUMB-
ING - STANDARD PROCEDURE - REFRIGERANT
RECOVERY)

(4) Drain the engine cooling system(Refer to 7 -

COOLING - STANDARD PROCEDURE).

(5) Remove the air cleaner hose and air distribu-

tion duct from the engine.

(6) Remove the spring type heater hose fasteners

at the dash panel and remove the hoses from heater
core. Plug the heater core inlet and outlet tubes to
prevent anti-freeze from spilling on the vehicle inte-
rior during removal. If an appropriate plug cannot be
found pull back carpet and use caution when remov-
ing the HVAC housing. Keep the heater tubes ele-
vated to prevent spillage of coolant.

(7) Remove one nut at expansion valve retaining

both A/C lines to expansion valve. After removing the
lines cap the expansion valve openings and the A/C
hose openings. This will prevent any dirt or moisture
from entering the refrigerant system during servic-
ing.

CAUTION: The lubricant used in this air condition-
ing system absorbs moisture readily (similar to
brake fluid). Do not leave any portion of the system
open for extended periods of time.

(8) Remove the three retaining nuts from the

studs. These studs project through the dash panel
into the engine compartment.

(9) Remove two screws to the defrost duct and

remove.

(10) Remove two nuts, and two screws attaching

the HVAC housing to the dash panel.

24 - 24

DISTRIBUTION

BLOWER MOTOR (Continued)

(11) Remove four nuts retaining the rear seat heat

duct, and remove.

(12) Remove the rear seat heat duct elbow push

pin fastener.

(13) Disconnect the HVAC harness connector.
(14) Gently pull the HVAC unit housing rearward

from the dash panel, being careful not to spill any
coolant into the passenger compartment.

DISASSEMBLY

(1) Remove the HVAC housing from the vehicle.

(Refer to 24 - HEATING & AIR CONDITIONING/
DISTRIBUTION/HVAC HOUSING - REMOVAL)

(2) Place HVAC housing on a workbench.
(3) Remove the heater core retaining screws. Pull

back on the retaining tabs and remove the heater
core from the housing.

(4) Remove the recirculation door actuator wiring.

Remove the actuator from the recirculation housing.
(Refer to 24 - HEATING & AIR CONDITIONING/
CONTROLS/RECIRCULATION DOOR ACTUATOR -
REMOVAL)

(5) Remove the lower distribution housing.
(6) Remove the mode door actuator. (Refer to 24 -

HEATING

AIR

CONDITIONING/CONTROLS/

MODE DOOR ACTUATOR - REMOVAL)

(7) Remove the blend door actuator. (Refer to 24 -

HEATING

AIR

CONDITIONING/CONTROLS/

BLEND DOOR ACTUATOR - REMOVAL)

(8) Remove the recirculation housing screws and

clip.

(9) Remove the blower motor wiring at the blower

motor resistor block/power module.

(10) Squeeze the blower motor wiring grommet

and push the grommet through the blower motor
cover.

(11) Remove the blower motor cover.
(12) Remove the blower motor retaining screws

and remove the motor.

(13) Remove the blower motor resistor block/power

module.

(14) Remove the evaporator temperature probe.

(Refer to 24 - HEATING & AIR CONDITIONING/
CONTROLS/EVAPORATOR TEMPERATURE SEN-
SOR - REMOVAL)

(15) Remove the vent door seal from the HVAC

housing.

(16) Remove the evaporator seal from the HVAC

housing.

(17) Remove the upper housing screws and clips.
(18) Separate the upper half of the HVAC housing

from the lower half.

(19) Remove the evaporator assembly from the

lower housing.

(20) Remove the blend door from the lower hous-

ing.

(21) Using a flat blade screwdriver, pinch in the

retaining tab at the base of the vent door. Pull up on
door and remove it from the HVAC housing.

(22) Remove the mode door actuating cam.
(23) Remove the screw at defrost door actuating

arm. Remove the defrost door link from the arm.

(24) Remove the defrost door arm from the lower

HVAC housing.

(25) Remove the link and defrost door from the

HVAC housing.

(26) Remove the vent door actuating arm from the

lower HVAC housing.

ASSEMBLY

(1) Install the vent door actuating arm to the

lower HVAC housing.

(2) Install the defrost door link to the defrost door.
(3) Install the defrost door and link into the HVAC

housing.

(4) Install the defrost door actuating arm and

retaining screw to the HVAC housing.

(5) Install the defrost door link to the actuating

arm.

(6) Line up the slots to the pegs on the mode door

cam, and install the mode door cam.

(7) Turn the HVAC housing over and snap in the

vent door to the vent door arm.

(8) Install the blend door in the HVAC housing.
(9) Install the evaporator into the lower HVAC

housing.

(10) Install the upper housing onto the lower hous-

ing.

(11) Install the screws that secure the two housing

halves to each other and tighten to 2.2 N·m (20 in.
lbs.).

(12) Install the evaporator and vent door seals on

the HVAC housing.

(13)

Insert the evaporator temperature sensor in

the evaporator. (Refer to 24 - HEATING & AIR CON-
DITIONING/CONTROLS/EVAPORATOR TEMPERA-
TURE SENSOR - INSTALLATION) If the same
evaporator is being used, the new probe must
not go into the same hole (in the evaporator
coil) that the old probe was removed. The evap-
orator is manufactured with three holes for probe
insertion. Insert the probe in the uppermost hole. If a
new evaporator is installed, place the evaporator
probe in the same location as on the previous evapo-
rator.

(14) Install the wiring at the evaporator tempera-

ture probe.

(15) Install the blower motor resistor block/power

module.

(16) Install the blower motor in the HVAC hous-

ing. Install the blower motor mounting screws and
tighten to 2.2 N·m (20 in. lbs.).

DISTRIBUTION

24 - 25

HVAC HOUSING (Continued)

(17) Thread the blower motor wiring through the

blower motor cover, and install the blower motor
housing cover.

(18) Seat the blower motor wiring grommet in the

blower motor housing cover.

(19) Install the blower motor wiring to the blower

motor resistor.

(20) Position the recirculation housing to the

HVAC housing. Install the retaining screws and clip.

(21) Install the blend door actuator. (Refer to 24 -

HEATING

AIR

CONDITIONING/CONTROLS/

BLEND DOOR ACTUATOR - INSTALLATION)

(22) Install the mode door actuator. (Refer to 24 -

HEATING

AIR

CONDITIONING/CONTROLS/

MODE DOOR ACTUATOR - INSTALLATION)

(23) Install the lower distribution housing.
(24) Install the recirculation door actuator and

wiring. (Refer to 24 - HEATING & AIR CONDITION-
ING/CONTROLS/RECIRCULATION DOOR ACTUA-
TOR - INSTALLATION)

(25) Install heater core in the HVAC housing.

Tighten the retaining screws to 2.2 N·m (20 in. lbs.).

INSTALLATION

WARNING: REVIEW THE WARNINGS IN THE FRONT
OF PLUMBING BEFORE PERFORMING THE FOL-
LOWING OPERATION. (Refer to 24 - HEATING & AIR
CONDITIONING/PLUMBING - WARNING)

(1) Position the HVAC housing to the dash panel.

Be certain that the evaporator condensate drain tube
and the mounting studs are inserted into their cor-
rect mounting holes.

(2) Connect the HVAC harness connector.
(3) Install the rear seat heat duct elbow push pin

fastener.

(4) Position the rear seat heat duct and install the

four retainer nuts. Tighten to 2.2 N·m (20 in. lbs.).

(5) Install the two nuts, and two screws attaching

the HVAC housing to the dash panel. Tighten to 4.5
N·m (40 in. lbs.).

(6) Position the defrost duct and install the two

retainer screws. Tighten to 2.2 N·m (20 in. lbs.).

(7) Install the nuts on the HVAC housing mount-

ing studs on the engine compartment side of the
dash panel. Tighten to 7 N·m (60 in. lbs.).

(8) Unplug or remove the tape from liquid and suc-

tion lines, and the expansion valve. Connect the lines
to the expansion valve and tighten the retaining nut
to 23 N·m (17 ft. lbs.).

(9) Install the heater hoses to the heater core and

install the spring type hose fasteners and fill the
engine cooling system(Refer to 7 - COOLING - STAN-
DARD PROCEDURE).

(10) Install the air cleaner hose and air distribu-

tion duct(Refer to 9 - ENGINE/AIR INTAKE SYS-
TEM/AIR CLEANER ELEMENT - INSTALLATION).

(11) Evacuate the refrigerant system. (Refer to 24 -

HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE - REFROGERANT SYS-
TEM EVACUATE)

(12) Charge the refrigerant system. (Refer to 24 -

HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE - REFRIGERANT SYS-
TEM CHARGE)

(13) Install the instrument panel in the vehicle(Re-

fer to 23 - BODY/INSTRUMENT PANEL/INSTRU-
MENT PANEL ASSEMBLY - INSTALLATION).

(14) Connect the negative battery cable remote ter-

minal to the remote battery post(Refer to 8 - ELEC-
TRICAL/BATTERY

SYSTEM/CABLES

INSTALLATION).

INSTRUMENT PANEL
DEMISTER DUCTS

DESCRIPTION

The side window demisters direct air from the

heater assembly through the outlets located on the
top corners of the instrument panel, to the side win-
dows.

OPERATION

Side window demisting is performed when the

mode selector is on FLOOR, DEFROST, MIX OR BI-
LEVEL setting.

24 - 26

DISTRIBUTION

HVAC HOUSING (Continued)

Content .. 396 397 398 399 ..