2002 CHRYSLER CARAVAN wheel

Fig. 176 ROOF PANEL/ROOF RAIL - SHORT WHEEL BASE ONLY
RSBODY STRUCTURE23 - 259
WELD LOCATIONS (Continued)
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(3) The calibration procedure should take less than
two minutes to complete for the manual heater-A/C
control, and less than twenty seconds for the ATC
heater-A/C control. When the LEDs or graphics stop
flashing, the calibration procedure is complete.
(4) If the LEDs or graphics continue to flash
beyond the normal three minute (manual) or twenty
second (ATC) calibration time, it indicates that the
heater-A/C control has detected a failure and a Diag-
nostic Trouble Code (DTC) has been set. Use a
DRBIIItscan tool to perform further diagnosis. Refer
to the appropriate diagnostic information. The LEDs
or graphics will continue to flash even after the igni-
tion switch is cycled Off and On, until a successful
calibration is completed or until the vehicle has been
driven about 13 kilometers (8 miles).
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 - REMOV-
AL).
(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 heater-A/C
control (Fig. 1).
(5) Remove the six screws that secure the heater-
A/C control to the back of the instrument panel cen-
ter bezel.
(6) Remove the heater-A/C control from the instru-
ment panel center bezel.
INSTALLATION
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) Position the heater-A/C control onto the back of
instrument panel center bezel.
(2) Install and tighten the six screws that secure
the heater-A/C 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 the receptacle on the back of
the heater-A/C control.
(4) Reinstall 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.
Fig. 1 Heater-A/C Control
1 - INFRARED SENSOR JUMPER CONNECTOR (ATC ONLY)
2 - INFRARED SENSOR JUMPER HARNESS (ATC ONLY)
3 - HEATER-A/C CONTROL
4 - SCREW (6)
5- INSTRUMENT PANEL CENTER BEZEL
RSCONTROLS - FRONT24-9
A/C HEATER CONTROL (Continued)
ProCarManuals.com

REMOVAL
The single zone heating and air conditioning sys-
tem is equipped with a single blend door actuator.
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 pro-
cedures can be used for each of these actuators.
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 silencer from beneath the driver
side end of the instrument panel. (Refer to 23 -
BODY/INSTRUMENT PANEL/INSTRUMENT
PANEL SILENCER - REMOVAL).
(3) Remove the three screws that secure the heater
core shield to the left end of the HVAC distribution
housing (Fig. 4).(4) Pull the heater core shield rearward far enough
to disengage the two location tabs that position the
front of the shield to the receptacles in the two lower
finger formations of the heater/ air conditioner hous-
ing near the dash panel.
(5) Remove the heater core shield from the distri-
bution housing.
(6) Disconnect the HVAC wire harness connector
for the blend door actuator from the actuator connec-
tor receptacle (Fig. 5).
(7) Remove the two screws that secure the blend
door actuator to the distribution housing.
(8) Remove the blend door actuator from the dis-
tribution housing.
INSTALLATION
(1) Position the blend door actuator onto the heat-
er/air conditioner 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 and tighten the two screws that secure
the blend door actuator to the distribution housing.
Tighten the screws to 2 N´m (17 in. lbs.).
(3) Reconnect the HVAC wire harness connector
for the blend door actuator to the actuator connector
receptacle.
(4) Position the heater core shield onto the distri-
bution housing. Be certain that the two location tabs
on the front of the shield are engaged in the recepta-
cles in the two lower finger formations of the evapo-
rator housing near the dash panel.
Fig. 4 Heater Core Shield
1 - HEATER/ AIR CONDITIONER HOUSING
2 - HEATER CORE SHIELD
3 - DISTRIBUTION HOUSING
4 - SCREWS (3)
5 - LOCATION TABS (2)
Fig. 5 Blend Door Actuator
1 - CONNECTOR
2 - MODE DOOR ACTUATOR
3 - SCREW (2)
4 - DRIVER BLEND DOOR ACTUATOR (DUAL-ZONE ONLY)
5 - HEATER CORE
6 - BLEND DOOR ACTUATOR (SINGLE ZONE) OR PASSENGER
BLEND DOOR ACTUATOR (DUAL-ZONE)
24 - 12 CONTROLS - FRONTRS
BLEND DOOR ACTUATOR (Continued)
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BLOWER MOTOR RESISTOR
DESCRIPTION
A blower motor resistor is used on this model when
it is equipped with the manual heater-A/C control
(Fig. 9). Models equipped with the optional Auto-
matic Temperature Control (ATC) use a blower power
module, instead of the blower motor resistor. The
blower motor resistor is installed in a mounting hole
in the heater/AC housing, directly behind the glove
box opening of the instrument panel. The resistor
consists of a molded plastic mounting plate with two
integral connector receptacles. Concealed behind the
mounting plate within the heater/AC housing are
four coiled resistor wires contained within a protec-
tive stamped steel cage. The resistor mounting plate
is secured with two screws to the heater/AC housing
and is accessed for service by rolling down the glove
box from the instrument panel.
The blower motor resistor wires will get hot when
in use. Do not touch the resistor wires or the protec-
tive cage if the blower motor has been running. The
blower motor resistor cannot be adjusted or repaired
and, if faulty or damaged, it must be replaced.
OPERATION
The blower motor resistor is connected to the vehi-
cle electrical system through a dedicated take out
and connector of the instrument panel wire harness.
A second connector receptacle receives the pigtail
wire connector from the blower motor. The blower
motor resistor has multiple resistor wires, each ofwhich will reduce the current flow through the
blower motor to change the blower motor speed. The
blower motor switch in the manual heater-A/C con-
trol directs the ground path for the blower motor
through the correct resistor wire to obtain the
selected speed. With the blower motor switch in the
lowest speed position, the ground path for the motor
is applied through all of the resistor wires. Each
higher speed selected with the blower motor switch
applies the blower motor ground path through fewer
of the resistor wires, increasing the blower motor
speed. When the blower motor switch is in the high-
est speed position, the blower motor resistor wires
are bypassed and the blower motor receives a direct
path to ground through the blower motor switch. The
blower motor resistor may be diagnosed using con-
ventional diagnostic tools and methods.
DIAGNOSIS AND TESTING - BLOWER MOTOR
RESISTOR
Refer to the appropriate wiring information. The
wiring information includes wiring diagrams, proper
wire and connector repair procedures, details of wire
harness routing and retention, connector pin-out
information and location views for the various wire
harness connectors, 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 ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Disconnect and isolate the battery negative
cable.
(2) Disconnect the instrument panel wire harness
connector for the blower motor resistor and the
blower motor pigtail wire connector from the resistor
connector receptacles.
(3) Check for continuity between each of the
blower motor switch input terminals of the blower
motor resistor and the resistor output terminal. In
each case there should be continuity. If OK, repair
the instrument panel wire harness circuits between
the blower motor switch and the blower motor resis-
tor or the blower motor pigtail wires as required. If
not OK, replace the faulty blower motor resistor.
Fig. 9 Blower Motor Resistor
1 - BLOWER MOTOR RESISTOR
2 - INSTRUMENT PANEL WIRE HARNESS
3 - SCREW (2)
4 - GLOVE BOX OPENING LOWER REINFORCEMENT
5 - BLOWER MOTOR PIGTAIL WIRE
6 - EVAPORATOR HOUSING
RSCONTROLS - FRONT24-15
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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 BLOWER MOTOR RESISTOR MAY
GET VERY HOT DURING NORMAL OPERATION. IF
THE BLOWER MOTOR WAS TURNED ON, WAIT
FIVE MINUTES TO ALLOW THE BLOWER MOTOR
RESISTOR TO COOL BEFORE PERFORMING DIAG-
NOSIS OR SERVICE. FAILURE TO TAKE THIS PRE-
CAUTION CAN RESULT IN PERSONAL INJURY.
CAUTION: Do not operate the blower motor with the
blower motor resistor removed from the circuit.
Failure to take this precaution can result in vehicle
damage.
(1) Disconnect and isolate the battery negative
cable.
(2) Open the glove box.
(3) Flex both sides of the glove box bin inward
near the top far enough for the rubber glove box stop
bumpers to clear the sides of the glove box opening,
then roll the glove box downward.
(4) Reach through the glove box opening to access
and disconnect the instrument panel wire harness
connector for the blower motor resistor from the
resistor connector receptacle (Fig. 10).
(5) Reach through the glove box opening to access
and disconnect the blower motor pigtail wire connec-
tor from the resistor connector receptacle.
(6) Remove the two screws that secure the blower
motor resistor to the evaporator housing.
(7) Remove the blower motor resistor from the
evaporator housing.
INSTALLATION
CAUTION: Do not operate the blower motor with the
blower motor resistor removed from the circuit.
Failure to take this precaution can result in vehicle
damage.(1) Position the blower motor resistor into the
evaporator housing.
(2) Install and tighten the two screws that secure
the blower motor resistor to the evaporator housing.
Tighten the screws to 2 N´m (17 in. lbs.).
(3) Reconnect the blower motor pigtail wire con-
nector to the blower motor resistor connector recep-
tacle.
(4) Reconnect the instrument panel wire harness
connector for the blower motor resistor to the resistor
connector receptacle.
(5) Flex both sides of the glove box bin inward
near the top far enough for the rubber glove box stop
bumpers to clear the sides of the glove box opening,
then roll the glove box upward.
(6) Close and latch the glove box.
(7) Reconnect the battery negative cable.
COMPRESSOR CLUTCH
DESCRIPTION
The compressor clutch assembly consists of a sta-
tionary electromagnetic coil with a zener diode, a hub
bearing and pulley assembly, and a clutch plate (Fig.
11). The electromagnetic coil unit and the hub bear-
ing and pulley assembly are each retained on the
nose of the compressor front housing with snap rings.
The clutch plate is keyed or splined to the compres-
sor shaft, and secured with a bolt.
Fig. 10 Blower Motor Resistor
1 - BLOWER MOTOR RESISTOR
2 - INSTRUMENT PANEL WIRE HARNESS
3 - SCREW (2)
4 - GLOVE BOX OPENING LOWER REINFORCEMENT
5 - BLOWER MOTOR PIGTAIL WIRE
6 - EVAPORATOR HOUSING
24 - 16 CONTROLS - FRONTRS
BLOWER MOTOR RESISTOR (Continued)
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The compressor clutch plate and pulley unit, or the
clutch coil are available for separate service replace-
ment. The clutch coil zener diode is integral to the
clutch coil pigtail wire and connector and, if faulty or
damaged, the clutch electromagnetic coil unit must
be replaced.
OPERATION
The compressor clutch components provide the
means to engage and disengage the compressor from
the engine serpentine accessory drive belt. When the
clutch coil is energized, it magnetically draws the
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, the Powertrain Control Mod-ule (PCM) in the engine compartment, and the com-
pressor clutch relay in the Intelligent Power Module
(IPM). The PCM may delay compressor clutch
engagement for up to thirty seconds. (Refer to 8 -
ELECTRICAL/ELECTRONIC CONTROL MOD-
ULES/POWERTRAIN CONTROL MODULE -
DESCRIPTION - PCM OPERATION).
STANDARD PROCEDURE
STANDARD PROCEDURE - COMPRESSOR
CLUTCH AIR GAP
If a new clutch plate and/or clutch pulley are being
used, the air gap between the clutch plate and clutch
pulley must be checked using the following proce-
dure:
(1) Using feeler gauges, measure the air gap
between the clutch plate and the clutch pulley fric-
tion surfaces.
(2) If the air gap is not between 0.5 and 0.9 mm
(0.020 and 0.035 in.), add or subtract shims until the
desired air gap is obtained.
NOTE: The shims may compress after tightening
the compressor shaft bolt. Check the air gap in four
or more places on the clutch plate to verify that the
air gap is still correct. Spin the clutch pulley before
making the final air gap check.
STANDARD PROCEDURE - COMPRESSOR
CLUTCH BREAK-IN
After a new compressor clutch has been installed,
check that the compressor clutch coil is performing to
specifications. (Refer to 24 - HEATING & AIR CON-
DITIONING/CONTROLS - FRONT/COMPRESSOR
CLUTCH COIL - DIAGNOSIS AND TESTING). If
the clutch coil is performing to specifications, per-
form the compressor clutch break-in procedure. This
procedure (burnishing) will seat the opposing friction
surfaces and provide a higher compressor clutch
torque capability.
(1) Set the heater-A/C controls to the A/C mode,
with the blower switch in the highest speed position.
(2) Start the engine and hold the engine speed at
1500 to 2000 rpm.
(3) Cycle the compressor clutch On and Off about
twenty times (five seconds On, then five seconds Off).
REMOVAL
The refrigerant system can remain fully charged
during compressor clutch, pulley, or coil replacement.
Although the compressor assembly must be removed
from its mounting, the compressor clutch can be ser-
vice with the compressor in the vehicle.
Fig. 11 Compressor Clutch - Typical
1 - CLUTCH PLATE
2 - SHAFT KEY (SOME MODELS)
3 - PULLEY AND BEARING
4 - CLUTCH COIL
5 - CLUTCH SHIMS
6 - SNAP RING
7 - SNAP RING
RSCONTROLS - FRONT24-17
COMPRESSOR CLUTCH (Continued)
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it to the linkage that drives the mode door. The mode
door actuator does not require mechanical indexing
to the mode door linkage, as it is electronically cali-
brated 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 heater-
A/C control module through the vehicle electrical sys-
tem by a dedicated two-wire take out and connector
of the HVAC wire harness. The mode door actuator
can move the mode 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 con-
nection low, the mode door will move in one direction.
When the module reverses the polarity of the voltage
to the motor, the mode door moves in the opposite
direction. When the module makes the voltage to
both connections high or both connections low, the
mode 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 mode door actuator and the mode
door. The heater-A/C control module learns the mode
door stop positions during the calibration procedure
and will store a Diagnostic Trouble Code (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 the appropriate
diagnostic information.
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 silencer from beneath the driver
side end of the instrument panel. (Refer to 23 -
BODY/INSTRUMENT PANEL/INSTRUMENT
PANEL SILENCER - REMOVAL).(3) Disconnect the HVAC wire harness connector
for the mode door actuator from the actuator connec-
tor receptacle (Fig. 21).
(4) Remove the two screws that secure the mode
door actuator to the distribution housing.
(5) Remove the mode door actuator from the distri-
bution housing.
INSTALLATION
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) Position the mode door actuator onto the heat-
er/AC housing. If necessary, rotate the actuator
slightly to align the splines on the actuator output
shaft with those in the mode door linkage.
Fig. 21 Mode Door Actuator
1 - CONNECTOR
2 - MODE DOOR ACTUATOR
3 - SCREW (2)
4 - DRIVER BLEND DOOR ACTUATOR (DUAL-ZONE ONLY)
5 - HEATER CORE
6 - BLEND DOOR ACTUATOR (SINGLE ZONE) OR PASSENGER
BLEND DOOR ACTUATOR (DUAL-ZONE)
RSCONTROLS - FRONT24-25
MODE DOOR ACTUATOR (Continued)
ProCarManuals.com

(2) Install and tighten the two screws that secure
the mode door actuator to the distribution housing.
Tighten the screws to 2 N´m (17 in. lbs.).
(3) Reconnect the HVAC wire harness connector
for the mode door actuator to the actuator connector
receptacle.
(4) Reinstall the silencer under the driver side end
of the instrument panel. (Refer to 23 - BODY/IN-
STRUMENT PANEL/INSTRUMENT PANEL
SILENCER - INSTALLATION).
(5) Reconnect the battery negative cable.
(6) Perform the heater-A/C 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
DESCRIPTION
A blower power module is used on this model when
it is equipped with the optional Automatic Tempera-
ture Control (ATC) (Fig. 22). Models equipped with
the standard manual heater-A/C control use a blower
motor resistor, instead of the blower power module.
The blower power module is installed in a mounting
hole in the evaporator housing, directly behind the
glove box opening of the instrument panel. The mod-
ule 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 module mounting plate is
secured with two screws to the evaporator housingand is accessed for service by rolling down the glove
box from the instrument panel.
The power module heat sink will get hot when in
use. Do not touch the heat sink if the blower motor
has been running. The blower power module cannot
be adjusted or repaired and, if faulty or damaged, it
must be replaced.
OPERATION
The blower power module is connected to the vehi-
cle electrical system through a dedicated take out
and connector of the instrument panel wire harness.
A second connector receptacle receives the pigtail
wire connector from the blower motor. The blower
power module allows the microprocessor-based Auto-
matic 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 programming 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 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 power module is diagnosed using a DRBIIIt
scan tool. Refer to the appropriate diagnostic infor-
mation.
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) Open the glove box.
(3) Flex both sides of the glove box bin inward
near the top far enough for the rubber glove box stop
bumpers to clear the sides of the glove box opening,
then roll the glove box downward.
(4) Reach through the glove box opening to access
and disconnect the instrument panel wire harness
Fig. 22 Power Module
1 - POWER MODULE
2 - LOWER GLOVE BOX OPENING REINFORCEMENT
3 - EVAPORATOR HOUSING
24 - 26 CONTROLS - FRONTRS
MODE DOOR ACTUATOR (Continued)
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