air conditioning CHRYSLER CARAVAN 2005 Workshop Manual

TEMPERATURE CONTROL
If the heater outlet air temperature cannot be
adjusted with the temperature control knob on the
A/C-heater control panel, the following could require
service:
²Blend door binding.
²Faulty blend door actuator.
²Faulty A/C-heater control.
²Faulty related wiring harness or connectors.²Improper engine coolant temperature.
SPECIFICATIONS
A/C SYSTEM
The R-134a refrigerant system charge capacity for
this vehicle can be found on the underhood Specifica-
tion Label.
SYSTEM SPECIFICATIONS
Item Description Notes
A/C Compressor Denso 10S17 ± 2.4L/2.5L/2.8L/3.3L
without rear A/C
Denso 10S20 ± 3.3L/3.8L with rear
A/CND-8 PAG Oil
Freeze±up Control Evaporator temperature sensor HVAC housing mounted (RS models),
Evaporator mounted (RG models) - input to
A/C-heater control module
Low PSI Control A/C pressure transducer Liquid line mounted - input to Powertrain Control
Module (PCM) - PCM opens compressor clutch
relay above 200 kPa (29 psi)
High PSI Control A/C pressure transducer Liquid line mounted - input to PCM - PCM
opens compressor clutch relay below 3100 kPa
(450 psi)
High Pressure relief valve Compressor mounted - opens above 3445-4135
kPa (500-600 psi), closes below 2756 kPa (400
psi)
Compressor Clutch Coil
DrawDenso 10S17 ± 3.3 amps @ 12V  
0.5V @ 21É C (70É F)
Denso 10S20 ± 2.2 amps @ 12V  
0.5V @ 21É C (70É F)
Compressor Clutch Air
Gap0.35 - 0.60 mm (0.014 - 0.024 in.)
TORQUE SPECIFICATIONS
Description N´m Ft. Lbs. In. Lbs.
A/C Compressor Shaft Bolt 17.5 ± 155
A/C Compressor Mounting Bolts (2.4L/2.5L/2.8L) 28 21 ±
A/C Compressor Mounting Bolts (3.3L/3.8L) 54 40 ±
A/C Compressor Mounting Bracket Bolts (2.4L) 54 40 ±
A/C Condenser Mounting Bracket Screws 5 ± 45
A/C Expansion Valve Screws 11 ± 97
A/C-Heater Control Screws 2 ± 17
Blend Door Actuator Screws 2 ± 17
Blower Motor Screws 2 ± 17
Blower Motor Power Module Screws (ATC) 2 ± 17
Blower Motor Resistor Block Screws (MTC) 2 ± 17
Center Bezel Outlet Screws 2 ± 17
RSHEATING & AIR CONDITIONING24-11
HEATING & AIR CONDITIONING (Continued)

Description N´m Ft. Lbs. In. Lbs.
Distribution Housing Screws 2 ± 17
Discharge Line to Compressor Nut 23 17 ±
Discharge Line to Condenser Nut 23 17 ±
Front Fascia Screws 6 ± 53
Front Fascia Grille Insert Screws 2 ± 17
Heater Core Mounting Plate Screws 2 ± 17
Heater Core Sealing Plate Screws 3 ± 26
Hood Latch Screws 14 ± 123
HVAC Housing Bracket Bolt 3 ± 26
HVAC Housing Mounting Nuts 7 ± 62
HVAC Housing Mounting Bolts 4 ± 35
Liquid Line to Condenser Nut 23 17 ±
Liquid Line to Receiver/drier Bolt 11 ± 97
Lower Air inlet Housing Screws 2 ± 17
Mode Door Actuator Screws 2 ± 17
Quarter Trim Panel Attaching Bracket Screws 2 ± 17
Rear Blower Motor Screws 2 ± 17
Rear Blower Motor Power Module Screws (ATC) 2 ± 17
Rear Blower Motor Resistor Block Screws (MTC) 2 ± 17
Rear Capture Plate Screw 2 ± 17
Rear Evaporator Line Seal Plate to Rear Expansion
Valve Nut23 17 ±
Rear Expansion Valve Bracket Nut 23 17 ±
Rear Expansion Valve Bracket Screws 2 ± 17
Rear Expansion Valve to Rear Evaporator Screws 11 ± 97
Rear Floor Heat Duct Screws 2 ± 17
Rear HVAC Housing Screws 2 ± 17
Rear HVAC Housing Mounting Screws 11 ± 97
Rear HVAC Housing Stud Nuts 9 ± 80
Rear Mode Door Actuator Screws 2 ± 17
Receiver/drier Bracket Nuts 10 ± 89
Recirculation Door Actuator Screws 2 ± 17
Refrigerant Lines to Expansion Valve Nut 23 17 ±
Suction Line to Compressor Nut 23 17 ±
Cabin Heater Air Intake Pipe Screws 7 ± 62
Cabin Heater M6 Bolts 7 ± 62
Cabin Heater M8 Bolts 23 17 ±
Cabin Heater Seat Hex Nut 60 44 ±
Underbody Liquid Line Fitting 23 17 ±
Underbody Refrigerant Line Sealing Plate Bolt/Nut 23 17 ±
Underbody Suction Line Fitting 23 17 ±
Upper Air Inlet Housing Screws 2 ± 17
24 - 12 HEATING & AIR CONDITIONINGRS
HEATING & AIR CONDITIONING (Continued)

clutch plate into contact with the clutch pulley and
drives the compressor shaft. When the coil is not
energized, the pulley freewheels on the clutch hub
bearing, which is part of the pulley.
A zener diode is connected in parallel with the
clutch electromagnetic coil. This diode controls the
dissipation of voltage induced into the coil windings
by the collapsing of the electromagnetic fields that
occurs when the compressor clutch is disengaged.
The zener diode dissipates this induced voltage by
regulating a current path to ground. This arrange-
ment serves to protect other circuits and components
from potentially damaging voltage spikes in the vehi-
cle electrical system that might occur if the voltage
induced in the clutch coil windings could not be dis-
sipated.
The compressor clutch engagement is controlled by
several components: the heater-A/C controls in the
passenger compartment, the A/C pressure transducer
on the liquid line, the evaporator temperature sensor
on the expansion valve for automatic temperature
control (ATC) system or on the HVAC housing for
manual temperature control (MTC) system, the Pow-
ertrain Control Module (PCM) in the engine compart-
ment, and the compressor clutch relay in the
Integrated Power Module (IPM). The PCM may delay
compressor clutch engagement for up to thirty sec-
onds (Refer to 8 - ELECTRICAL/ELECTRONIC
CONTROL MODULES/POWERTRAIN CONTROL
MODULE - DESCRIPTION - PCM OPERATION).
DIAGNOSIS AND TESTING
A/C COMPRESSOR CLUTCH COIL
The air conditioning compressor clutch coil electri-
cal circuit is controlled by the powertrain control
module (PCM) through the A/C compressor clutch
relay, which is located in the integrated power mod-
ule (IPM) in the engine compartment. Begin testing
of a suspected compressor clutch coil problem by per-
forming the preliminary checks.
PRELIMINARY CHECKS
(1) If the compressor clutch will not engage, verify
the refrigerant charge level (Refer to 24 - HEATING
& AIR CONDITIONING/PLUMBING - FRONT/RE-
FRIGERANT - DIAGNOSIS AND TESTING -
REFRIGERANT CHARGE LEVEL). If the refriger-
ant charge level is OK, go to Step 2. If the refriger-
ant charge level is not OK, adjust the refrigerant
charge as required.
(2) If the A/C compressor clutch still will not
engage, disconnect the wire harness connector for the
A/C pressure transducer and check for battery cur-
rent at the connector with the engine running and
the A/C-heater control set to the A/C mode. If OK, go
to TESTS. If not OK, refer to Body Diagnostic Proce-
dures to perform further diagnosis.
TESTS
(1) Verify the battery state of charge (Refer to 8 -
ELECTRICAL/BATTERY SYSTEM/BATTERY -
DIAGNOSIS AND TESTING).
(2) Connect an ammeter (0 to 10 ampere scale
selected) in series with the clutch coil feed terminal.
Connect a voltmeter (0 to 20 volt scale selected) to
measure voltage across the battery and the clutch
coil.
(3) With the heater-A/C control in the A/C mode
and the blower at low speed, start the engine and
allow it to run at a normal idle speed.
(4) The compressor clutch should engage immedi-
ately, and the clutch coil voltage should be within
two volts of the battery voltage. If the coil voltage is
not within two volts of battery voltage, test the
clutch coil feed circuit for excessive voltage drop. If
the compressor clutch does not engage, refer to Body
Diagnostic Procedures to perform further diagnosis.
(5) For the acceptable A/C clutch coil current draw
specificationsrefer to 24 - HEATING & AIR CONDI-
TIONING - SPECIFICATIONS. Specifications apply
for a work area temperature of 21É C (70É F). If volt-
age is more than 12.5 volts, add electrical loads by
turning on electrical accessories until voltage reads
below 12.5 volts.
(a) If the compressor clutch coil current reading
is zero, the coil is open and must be replaced.
Fig. 1 A/C Compressor Clutch
1 - BOLT
2 - CLUTCH PLATE
3 - PULLEY AND BEARING
4 - FIELD COIL
5 - SNAP RING (2)
6 - SHIM
24 - 14 CONTROLS - FRONTRS
A/C COMPRESSOR CLUTCH/COIL (Continued)

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 center bezel from the instrument
panel (Refer to 23 - BODY/INSTRUMENT PANEL/
INSTRUMENT PANEL CENTER BEZEL -
REMOVAL).
(3) Place the instrument panel center bezel unit
face down on a suitable work surface. Take the
proper precautions to protect the center bezel from
cosmetic damage.
(4) If the vehicle is equipped with the optional
Automatic Temperature Control (ATC) system, dis-
connect the infrared sensor jumper harness connector
from the receptacle on the back of the A/C-heater
control (Fig. 9).
(5) Remove the six screws that secure the A/C-
heater control to the back of the instrument panel
center bezel.
(6) Remove the A/C-heater control from the instru-
ment panel center bezel.
INSTALLATION
(1) Position the A/C-heater control onto the back of
instrument panel center bezel.
(2) Install the six screws that secure the A/C-
heater control to the back of the instrument panel
center bezel. Tighten the screws to 2 N´m (17 in.
lbs.).
(3) If the vehicle is equipped with the optional
ATC system, reconnect the infrared sensor jumper
harness connector to A/C-heater control.
(4) Install the center bezel onto the instrument
panel (Refer to 23 - BODY/INSTRUMENT PANEL/
INSTRUMENT PANEL CENTER BEZEL - INSTAL-
LATION).
(5) 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 liquid
line between the receiver/drier and the expansion
valve in the right rear corner of the engine compart-
ment. An internally threaded hex fitting on the
transducer connects it to the externally threaded
Schrader-type fitting on the liquid line. A rubber
O-ring seals the connection between the transducer
and the liquid line fitting. Three terminals within a
molded plastic connector receptacle on the top of the
transducer connect it to the vehicle electrical system
through a wire lead and connector of the headlamp
and dash wire harness.
The A/C pressure transducer cannot be adjusted or
repaired and, if faulty or damaged, it must be
replaced.
OPERATION
The A/C pressure transducer monitors the pres-
sures in the high side of the refrigerant system
through its connection to a fitting on the liquid line.
The transducer will change its internal resistance in
response to the pressures it monitors. The power-
train control module (PCM) provides a five volt ref-
erence signal and a sensor ground to the transducer,
then monitors the output voltage of the transducer
on a sensor return circuit to determine refrigerant
pressure. The PCM is programmed to respond to this
and other sensor inputs by controlling the operation
of the A/C compressor clutch and the radiator cooling
fan to help optimize air conditioning system perfor-
Fig. 9 A/C-Heater Control ± ATC shown, MTC typical
1 - INFRARED SENSOR CONNECTOR (ATC ONLY)
2 - INFRARED SENSOR HARNESS (ATC ONLY)
3 - A/C-HEATER CONTROL
4 - SCREW (6)
5- INSTRUMENT PANEL CENTER BEZEL
24 - 20 CONTROLS - FRONTRS
A/C HEATER CONTROL (Continued)

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 air 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 air doors, which are controlled by two
blend door actuators. The single zone blend door
actuator is located on the driver's side end of the
HVAC housing, close to the middle of the distribution
housing. In the dual zone system, the same blend
door actuator used for the single zone system
becomes the passenger blend door actuator, and is
mechanically connected to only the passenger side
blend air door. In the dual zone system, a second sep-
arate blend door actuator is also located on the
driver side end of the HVAC housing, close to the
middle of the distribution housing, and is mechani-
cally connected to only the driver's side blend air
door.
The blend door actuators are interchangeable with
each other, as well as with the actuators for the
mode door and the recirculation air door. Each actua-
tor is contained within an identical black molded
plastic housing with an integral wire connector
receptacle. Two integral mounting tabs allow the
actuator to be secured with two screws to the distri-
bution housing. Each actuator also has an identical
output shaft with splines that connects it to the link-
age that drives the proper blend air door. The blend
door actuators do not require mechanical indexing to
the blend door linkage, as they are electronically cal-
ibrated by the heater-A/C control module.
OPERATION
The blend door actuators are connected to the A/C-
heater control through the vehicle electrical system
by a dedicated two-wire lead and connector of the
HVAC wire harness. The blend door actuator(s) can
move the blend-air door(s) in two directions. When
the A/C-heater control pulls the voltage on one side
of the motor connection high and the other connec-
tion low, the blend-air door will move in one direc-
tion. 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 A/C-
heater control uses a feedback signal positioning sys-
tem to monitor the operation and relative position of
the blend door actuator(s) and the blend-air door(s).
The A/C-heater control learns the blend-air door stoppositions during the calibration procedure and will
store a diagnostic trouble code (DTC) for any prob-
lems it detects in the blend door actuator circuits.
The blend door actuators are diagnosed using a
scan tool (Refer to 24 - HEATING & AIR CONDI-
TIONING - DIAGNOSIS AND TESTING and to 24 -
HVAC Electrical Diagnostics for more information).
The blend door actuators cannot be adjusted or
repaired and, if faulty or damaged, 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.
NOTE: The single zone heating and air conditioning
system is equipped with a single blend door actua-
tor. The dual zone system has two blend door
actuators, one for the driver side blend air door and
one for the passenger side blend air door. The
same service procedures can be used for each of
these actuators.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the silencer from beneath the driver
side end of the instrument panel. (Refer to 23 -
BODY/INSTRUMENT PANEL/INSTRUMENT
PANEL SILENCER - REMOVAL).
(3) Disconnect the wire harness connector from the
blend door actuator(s) (Fig. 11).
(4) Remove the two screws that secure the blend
door actuator to the distribution housing.
(5) Remove the blend door actuator.
INSTALLATION
(1) Position the blend door actuator onto the distri-
bution housing. If necessary, rotate the actuator
slightly to align the splines on the actuator output
shaft with those in the blend air door linkage.
(2) Install the two screws that secure the blend
door actuator to the housing. Tighten the screws to 2
N´m (17 in. lbs.).
24 - 22 CONTROLS - FRONTRS

The blower motor relay terminals are connected to
the vehicle electrical system through a receptacle in
the Integrated Power Module (IPM). The inputs and
outputs of the blower motor relay include:
²The common feed terminal (30) receives a bat-
tery current input from the battery through a B(+)
circuit at all times.
²The coil ground terminal (85) receives a ground
input through the front/rear blower motor relay con-
trol circuit only when the FCM electronically pulls
the control circuit to ground.
²The coil battery terminal (86) receives a battery
current input from the battery through a B(+) circuit
at all times.
²The normally open terminal (87) provides a bat-
tery current output to the blower motor resistor
(manual heater-A/C control) or blower power module
(automatic heater-A/C control) through a fuse in the
IPM on the fused front blower motor relay output cir-
cuit only when the blower motor relay coil is ener-
gized.
²The normally closed terminal (87A) is not con-
nected to any circuit in this application, but provides
a battery current output only when the blower motor
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. 13).
NOTE: Refer to the fuse and relay map on the inner
surface of the cover of the IPM for front blower
motor relay identification and location.
(3) Remove the front blower motor relay from the
IPM
INSTALLATION
NOTE: Refer to the fuse and relay map on the inner
surface of the cover of the integrated power module
(IPM) for front blower motor relay identification and
location.
(1) Position the front blower motor relay to the
proper receptacle in the IPM.
(2) Align the front blower motor relay terminals
with the terminal cavities in the IPM receptacle.
(3) Push down firmly on the front blower motor
relay until the terminals are fully seated in the ter-
minal cavities.
(4) Install the cover onto the IPM.(5) Reconnect the negative battery cable.
BLOWER MOTOR RESISTOR
BLOCK
DESCRIPTION
A blower motor resistor is used on this model when
it is equipped with the manual heater-A/C system.
Models equipped with the optional Automatic Tem-
perature Control (ATC) system use a blower power
module, instead of the blower motor resistor block
(Refer to 24 - HEATING & AIR CONDITIONING/
CONTROLS/POWER MODULE - DESCRIPTION).
The blower motor resistor block is mounted to the
rear of the HVAC housing, directly behind the glove
box opening in the instrument panel. The resistor
block consists of a molded plastic mounting plate
with two integral connector receptacles. Concealed
behind the mounting plate are four coiled resistor
wires contained within a protective stamped steel
cage. The blower motor resistor block is accessed for
service by removing the glove box from the instru-
ment panel.
OPERATION
The blower motor resistor block is connected to the
vehicle electrical system through a dedicated take
out and connector of the instrument panel wire har-
ness. A second connector receptacle receives the pig-
tail wire connector from the blower motor. The
blower motor resistor has multiple resistor wires,
Fig. 13 Front Blower Motor Relay
1 - INTEGRATED POWER MODULE (IPM)
2 - FRONT BLOWER MOTOR RELAY
2 - FRONT CONTROL MODULE (FCM)
24 - 24 CONTROLS - FRONTRS
BLOWER MOTOR RELAY (Continued)

(8) Run the HVAC Cool Down test to verify system
is operating properly (Refer to 24 - HEATING & AIR
CONDITIONING - DIAGNOSIS AND TESTING).
RS MODELS
(1) Install the evaporator temperature sensor into
the top of the HVAC housing.
(2) Connect the wire harness connector to the
evaporator temperature sensor.
(3) Install the instrument panel (Refer to 23 -
BODY/INSTRUMENT PANEL/INSTRUMENT
PANEL ASSEMBLY - INSTALLATION).
(4) Reconnect the negative battery cable.
INFRARED TEMPERATURE
SENSOR
DESCRIPTION
The infrared temperature sensor consists of two
infrared transducers that are concealed behind a
clear lens located near the bottom of the center panel
outlet near the top of the instrument panel center
bezel (Fig. 19). These sensors are used only on mod-
els equipped with the optional automatic tempera-
ture control (ATC) heating-A/C system. A molded
plastic connector receptacle on the bottom of the
panel outlet unit is concealed behind the center
bezel. A short, dedicated jumper wire harness routedbehind the center bezel connects the sensors directly
to the ATC A/C-heater control module near the bot-
tom of the center bezel. The infrared temperature
sensor is integral to the center bezel panel outlet
unit. The infrared sensors cannot be adjusted or
repaired and, if faulty or damaged, the center bezel
must be replaced.
OPERATION
The dual infrared temperature sensors provide
independent measurement inputs to the Automatic
Temperature Control (ATC) heater-A/C control mod-
ule that indicates the surface temperature of the
driver seat and front seat passenger seat occupants.
By using a surface temperature measurement, rather
than an air temperature measurement, the ATC sys-
tem is able to adjust itself to the comfort level as per-
ceived by the occupant. This allows the system to
detect and compensate for other ambient conditions
affecting comfort levels, such as solar heat gain or
evaporative heat loss. The ATC system logic responds
to the infrared sensor inputs by calculating and
adjusting the air flow temperature and air flow rate
needed to properly obtain and maintain the individ-
ually selected comfort level temperatures of both the
driver and passenger seat occupants. The ATC heat-
er-A/C control module continually monitors the infra-
red sensor circuits, and will store a Diagnostic
Trouble Code (DTC) for any problem it detects. This
DTC information can be retrieved and the infrared
temperature sensor diagnosed using a DRBIIItscan
tool. Refer to Body Diagnostic Procedures.
Fig. 18 Evaporator Temperature Sensor - RS Models
1 - EVAPORATOR TEMPERATURE SENSOR
2 - WIRE HARNESS CONNECTOR
3 - HVAC HOUSING
Fig. 19 Infrared Temperature Sensor ± RS shown,
RG typical
1 - INSTRUMENT PANEL CENTER BEZEL
2 - CENTER IP AIR OUTLETS
3 - INFRARED TEMPERATURE SENSOR
24 - 28 CONTROLS - FRONTRS
EVAPORATOR TEMPERATURE SENSOR (Continued)

INSTALLATION
(1) Position the mode door actuator onto the HVAC
distribution housing. If necessary, rotate the actuator
slightly to align the splines on the actuator output
shaft with those in the mode door linkage.
(2) Install the two screws that secure the mode
door actuator to the distribution housing. Tighten the
screws to 2 N´m (17 in. lbs.).
(3) Connect the wire harness connector to the
mode door actuator.
(4) Install the silencer under the driver side end of
the instrument panel (Refer to 23 - BODY/INSTRU-
MENT PANEL/INSTRUMENT PANEL SILENCER -
INSTALLATION).
(5) Reconnect the negative battery cable.
(6) Perform the A/C-heater control calibration pro-
cedure (Refer to 24 - HEATING & AIR CONDITION-
ING/CONTROLS - FRONT/A/C-HEATER CONTROL
- STANDARD PROCEDURE - HEATER-A/C CON-
TROL CALIBRATION).
POWER MODULE - BLOWER
MOTOR
DESCRIPTION
A blower motor power module is used on this
model when it is equipped with the optional Auto-
matic Temperature Control (ATC) system. Models
equipped with the standard manual heater-A/C sys-
tem use a blower motor resistor block, instead of the
blower motor power module (Refer to 24 - HEATING
& AIR CONDITIONING/CONTROLS/BLOWER
MOTOR RESISTOR BLOCK - DESCRIPTION).
The blower motor power module is mounted to the
rear of the HVAC housing, directly behind the glove
box opening in the instrument panel. The module
consists of a molded plastic mounting plate with two
integral connector receptacles. Concealed behind the
mounting plate is the power module electronic cir-
cuitry and a large finned, heat sink. The blower
motor power module is accessed for service by remov-
ing the glove box from the instrument panel.
OPERATION
The blower motor power module is connected to the
vehicle electrical system through a dedicated lead
and connector from the instrument panel wire har-
ness. A second connector receptacle receives a wire
lead connector from the blower motor. The blower
motor power module allows the microprocessor-based
Automatic Temperature Control (ATC) heater-A/C
control module to calculate and provide infinitely
variable blower motor speeds based upon either man-
ual blower switch input or the ATC programming
using a Pulse Width Modulated (PWM) circuit strat-
egy. The PWM voltage is applied to a comparator cir-
cuit which compares the PWM signal voltage to the
blower motor feedback voltage. The resulting output
drives the power module circuitry, which adjusts the
voltage output received from the blower motor relay
to change or maintain the desired blower speed. The
blower motor power module is diagnosed using a
DRBIIItscan tool. Refer to Body Diagnostic Proce-
dures.
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.
WARNING: THE HEAT SINK FOR THE BLOWER
MOTOR POWER MODULE MAY GET VERY HOT
DURING NORMAL OPERATION. IF THE BLOWER
MOTOR WAS TURNED ON PRIOR TO SERVICING
THE BLOWER MOTOR POWER MODULE, WAIT
FIVE MINUTES TO ALLOW THE HEAT SINK TO
COOL BEFORE PERFORMING DIAGNOSIS OR SER-
VICE. FAILURE TO TAKE THIS PRECAUTION CAN
RESULT IN PERSONAL INJURY.
24 - 30 CONTROLS - FRONTRS
MODE DOOR ACTUATOR (Continued)

(10) Remove the rear mode door actuator from
between the rear HVAC housing and the quarter
inner panel.
INSTALLATION
(1) Position the mode door actuator between the
rear HVAC housing and the quarter inner panel.
(2) Reconnect the rear HVAC wire harness connec-
tor to the rear mode door actuator.
(3) Position the rear mode door actuator onto the
rear HVAC housing. If necessary, rotate the actuator
slightly to align the splines on the actuator output
shaft with those in the mode door linkage.
(4) Install the two screws that secure the rear
mode door actuator to the rear HVAC housing.
Tighten the screws to 2 N´m (17 in. lbs.).
(5) Push the top of the rear HVAC housing back
into position against the right quarter inner panel.
(6) Install the screw that secures the front of the
rear HVAC housing to the right quarter inner panel.
Tighten the screw to 11 N´m (97 in. lbs.).(7) Install the screw that secures the back of the
rear HVAC housing to the right D-pillar. Tighten the
screw to 11 N´m (97 in. lbs.).
(8) Install the two screws that secure the top of
the quarter trim panel attaching bracket to the quar-
ter inner panel. Tighten the screws to 2 N´m (17 in.
lbs.).
(9) Reinstall the right quarter trim panel and
right D-pillar trim panel onto the quarter inner
panel (Refer to 23 - BODY/INTERIOR/QUARTER
TRIM PANEL - INSTALLATION).
(10) Reconnect the battery negative cable.
(11) Perform the heater-A/C control calibration
procedure (Refer to 24 - HEATING & AIR CONDI-
TIONING/CONTROLS - FRONT/A/C-HEATER CON-
TROL - STANDARD PROCEDURE - HEATER-A/C
CONTROL CALIBRATION).
POWER MODULE - REAR
BLOWER MOTOR
DESCRIPTION
A rear blower motor power module is used on this
model when it is equipped with the optional Auto-
matic Temperature Control (ATC) system. Models
equipped with the standard manual heater-A/C sys-
tem use a blower motor resistor block , instead of the
blower motor power module (Refer to 24 - HEATING
& AIR CONDITIONING/CONTROLS/BLOWER
MOTOR RESISTOR BLOCK - DESCRIPTION).
The rear blower motor power module is installed in
the back of the rear HVAC housing, directly above
the expansion valve. The module consists of a molded
plastic mounting plate with two integral connector
receptacles. Concealed behind the mounting plate
within the evaporator housing is the power module
electronic circuitry and a large finned, heat sink. The
power module is accessed for service by removing the
right quarter and D-pillar trim panels.
OPERATION
The rear blower motor power module is connected
to the vehicle electrical system through a dedicated
take out and connector of the rear HVAC wire har-
ness. A second connector receptacle receives the pig-
tail wire connector from the rear blower motor. The
rear blower motor power module allows the micropro-
cessor-based Automatic Temperature Control (ATC)
heater-A/C control module to calculate and provide
infinitely variable blower motor speeds based upon
either manual blower switch input or the ATC pro-
gramming using a Pulse Width Modulated (PWM)
circuit strategy. The PWM voltage is applied to a
comparator circuit which compares the PWM signal
voltage to the blower motor feedback voltage. The
Fig. 7 Rear HVAC Blend Door Actuator
1 - SCREW (2)
2 - MODE DOOR ACTUATOR
3 - SCREW (2)
4 - CONNECTOR
5 - BLEND DOOR ACTUATOR
6 - WIRE HARNESS CONNECTOR
24 - 40 CONTROLS - REARRS
MODE DOOR ACTUATOR - REAR (Continued)

whenever the ignition switch is in the On position
and the A/C-heater control power is turned on.
The blower motor receives battery current when-
ever the front blower motor relay is energized. The
front blower motor relay output circuit is protected
by a fuse in the Integrated Power Module (IPM)
located in the engine compartment near the battery.
In the manual heater-A/C system, the blower motor
speed is controlled by regulating the path to ground
through the blower control switch and the blower
motor resistor. In the ATC system, the blower motor
speed is controlled by an electronic blower motor
power module, which uses a pulse width modulated
input from the ATC module and feedback from the
blower motor to regulate the blower motor ground
path it provides. The blower motor and wheel are
used to control the velocity of air moving through the
HVAC housing by spinning the blower wheel within
the housing at the selected speed or, in the ATC sys-
tem, at the selected or programmed speed.
DIAGNOSIS AND TESTING
FRONT BLOWER MOTOR
BLOWER MOTOR INOPERATIVE
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.
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.BLOWER MOTOR ELECTRICAL DIAGNOSIS
(1) Check the fuse (Fuse 10 - 40 ampere) in the
Integrated Power Module (IPM). 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 On position. Be
certain that the A/C-heater control power is turned
on. Check for battery voltage at the fuse (Fuse 10 -
40 ampere) in the IPM. If OK, go to Step 3. If not
OK, check the front blower motor relay.
(3) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Disconnect the front HVAC wire harness connector
for the front blower motor resistor block (Manual
Temperature Control) or the front blower motor
power module (Automatic Temperature Control) from
the resistor or module connector receptacle. Recon-
nect the battery negative cable. Turn the ignition
switch to the On position. Be certain that the A/C-
heater control power is turned on. Check for battery
voltage at the fused front blower motor relay output
circuit cavity of the front HVAC wire harness connec-
tor for the front blower motor resistor block (MTC) or
the front blower motor power module (ATC). If OK,
go to Step 4. If not OK, repair the open fused front
blower motor relay output circuit to the IPM as
required.
(4) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Disconnect the front blower motor pigtail wire con-
nector from the connector receptacle of the front
blower motor resistor block (MTC) or the front
blower motor power module (ATC). Use jumper wires
to connect a battery and ground feeds to the blower
motor pigtail wire connector. The blower motor
should operate. If OK with MTC, proceed to diagno-
sis of the front blower motor resistor block (Refer to
24 - HEATING & AIR CONDITIONING/CONTROLS
- FRONT/BLOWER MOTOR RESISTOR - DIAGNO-
SIS AND TESTING). If OK with ATC, use a DRBIII
scan tool to diagnose the front blower motor power
module. Refer to Body Diagnostic information. If not
OK with MTC or ATC, replace the faulty front blower
motor.
BLOWER MOTOR NOISE OR VIBRATION
Refer to the Blower Motor Noise/Vibration Diagno-
sis chart for basic checks of the blower motor when a
vibration or noise is present (Fig. 7).
24 - 46 DISTRIBUTION - FRONTRS
BLOWER MOTOR (Continued)