2005 CHRYSLER CARAVAN instrument panel

²a rotary adjustment knob for temperature.
²a rotary adjustment for fan speed control.
AUTOMATIC TEMPERATURE CONTROL
Two different automatic temperature control (ATC)
heating-A/C systems are available for this model
depending on the market.
The Dual-Zone ATC system allows the driver and
front occupants to each select individual comfort tem-
peratures.
The Three-Zone ATC system allows both the driver
and front occupants and the rear intermediate occu-
pants to select individual comfort temperatures.
NOTE: Individual comfort temperatures are the per-
ceived temperature level at the individual seating
areas, NOT the actual passenger compartment air
temperature.
The ATC system includes a particulate air filter.
The filter element is the same size as the A/C evap-
orator to ensure ample capacity. A door at the base of
the HVAC housing below the glove box provides easy
access to the filter element.
The ATC computer utilizes integrated circuitry and
information carried on the programmable communi-
cations interface (PCI) data bus network to monitor
many sensors and switch inputs throughout the vehi-
cle. In response to those inputs, the internal circuitry
and programming of the ATC computer allow it to
control electronic functions and features of the ATC
system. The inputs to the ATC computer are:
²Vehicle Speed/Engine RPM± The ATC com-
puter monitors engine rpm, vehicle speed and mani-
fold absolute pressure information from the
powertrain control module (PCM).
²Coolant Temperature± ATC computer moni-
tors coolant temperature received from the PCM and
converts it to degrees Fahrenheit.
²Ambient Temperature± ATC computer moni-
tors ambient temperature from the compass mini trip
computer (CMTC) and converts it to degrees Fahren-
heit.
²Engine Miscellaneous Sensor Status±ATC
computer monitors A/C disable information from the
PCM.
²Refrigerant Pressure± ATC computer moni-
tors barometric pressure, intake air temperature,
high side pressure and methanol content as broad-
cast by the PCM.
²Door Ajar Status± The ATC computer moni-
tors driver front door, passenger front door, left rear
door, right rear door and liftgate ajar information, as
identified by the body control module (BCM), to
determine if all in-car temperatures should be main-
tained.²Dimming± The ATC computer monitors dim-
ming status from the BCM to determine the required
level of brightness and will dim accordingly.
²Vehicle Odometer± The ATC computer moni-
tors the vehicle odometer information from the BCM
to prevent flashing the vacuum-flourescent (VF) dig-
ital display icons if the manual motor calibration or
manual cool down tests have failed. Flashing of the
display icons will cease when the vehicle odometer is
greater than 3 miles.
²English/Metric± The ATC computer monitors
the English/Metric information broadcast by the
CMTC. The set temp displays for both the front and
rear control heads will be set accordingly.
²Vehicle Identification Number± The ATC
computer monitors the last eight characters of the
VIN broadcast by the PCM and compares it to the
information stored in EEPROM. If it is different, the
new number will be stored over the old one and a
motor calibration shall be initiated.
²A/C System Information± The ATC computer
will send a message for evaporator temperature too
low, fan blower relay status, evaporator sensor fail-
ure, rear window defogger relay and A/C select.
FRONT CONTROL PANEL
The front A/C-heater control and integral computer
is mounted in the instrument panel and contains:
²a power button which allows the system to be
completely turned off. The display is blank when the
system is off.
²a rocker switch that selects a cool-down rate.
LO-AUTO or HI-AUTO are displayed when the sys-
tem is in automatic operation.
²three rocker switches that select comfort temper-
atures from 15É to 30É C (59É to 85É F), which are
shown in the VF digital display. If the set temp is 15É
C (59É F) and the down button is pressed, the set
temp value will become 13É C (55É F) but the display
will show LO. If the set temp is 29É C (85É F) and the
up button is pressed, the set temp value will become
32É C (90É F) but the display will show HIGH. Tem-
peratures can be displayed in either metric or Fahr-
enheit, which is controlled from the overhead console.
²an air conditioning button that allows the com-
pressor to be turned off. A Snowflake symbol is illu-
minated when air conditioning is on, whether under
manual or automatic control.
²an air recirculation button. A Recirculation sym-
bol appears in the display when the button is
pressed, or when the system exceeds 80 percent recir-
culated air under automatic control due to high air
conditioning demand.
²a rear window defogger on/off switch. A graphic
symbol shows when the defroster is on.
RSHEATING & AIR CONDITIONING24-3
HEATING & AIR CONDITIONING (Continued)

²a rotary knob for front fan speed selection can
override the automatic controls. LEDs surrounding
the knob show the current setting.
²a rotary knob for control of the rear system
(Three-Zone ATC system only).
²a rotary knob for mode control can override the
automatic controls. LEDs surrounding the knob show
the current setting.
²computer logic which remembers the settings of
the controls when the ignition is turned off and
retains those settings after a restart. If the system is
off when the ignition is turned off it will be off when
the engine is restarted, etc.
²computer logic which provides variable air recir-
culation under high temperature and humidity condi-
tions. Because recirculation is generally accompanied
by increased fan noise, the proportion of recirculated
to outside air gradually approaches full recirculation
over a broad temperature range.
²computer logic which enables additional heat for
diesel equipped vehicles by using a supplemental
engine coolant heater.
REAR CONTROL PANEL
The Three-Zone ATC sytem utilizes a rear control
panel centrally mounted on the headliner which
includes a VF digital display, a rocker control for
temperature and rotary controls for adjustment of
mode and fan speed of the rear heating-A/C system
by intermediate seat passengers.
OPERATION
HEATER AND AIR CONDITIONER
The heating and air conditioning systems pulls
outside (ambient) air through the cowl opening at the
base of the windshield and into the plenum chamber
above the heating, ventilation and air conditioning
(HVAC) housing, then through the evaporator coil.
Air flow can be directed either through or around the
heater core by adjusting the blend door with the tem-
perature control knob on the A/C-heater control
located on instrument panel. The air flow can then
be directed out from the panel, floor and defrost out-
lets 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 selec-
tor 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 system is a blend-
air type system. In a blend-air system, a blend door
controls the amount of conditioned air that is allowed
to flow through, or around, the heater core. The tem-
perature control knob determines the discharge air
temperature by actuating an electric motor, which
operates the blend door. This allows an almost imme-
diate control of the output air temperature of the sys-
tem.
On all models, the outside air intake can be shut
off by pressing the Recirculation button on the A/C-
heater control. This will operate a electric actuated
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.MANUAL SINGLE ZONE
²The temperature control knob enables continu-
ously variable proportioning of the conditioned air.
²The mode control knob enables continuously
variable proportioning of air flow between modes and
has detents adjacent to each icon.
²The blower control provides four separate speeds
and an Off position.
²When the heater-A/C system is off, the HVAC
computer closes the recirculation door to prevent out-
side air from entering the passenger compartment.
²Interior air may be recirculated to speed up
heating or cooling in all modes except defrost and
mix by pressing the Recirculate button on the A/C-
heater control.
²To reduce humidity for rapid defogging, the A/C
compressor runs automatically in modes from ªmixº
to full defrost when outside temperatures are above
freezing.
²Air conditioning is available in any mode by
pressing the snowflake, A/C on/off button.
24 - 4 HEATING & AIR CONDITIONINGRS
HEATING & AIR CONDITIONING (Continued)

MANUAL DUAL ZONE
²The two slide controls enable continuously vari-
able proportioning of the conditioned air.
²The mode control knob enables continuously
variable proportioning of air flow between modes and
has detents adjacent to each icon.
²The blower control provides four separate speeds
and an Off position.
²When the heater-A/C system is off, the HVAC
computer closes the recirculation door to prevent out-
side air from entering the passenger compartment.
²Interior air may be recirculated to speed up
heating or cooling in all modes except defrost and
mix by pressing the Recirculate button on the A/C-
heater control.
²To reduce humidity for rapid defogging, the A/C
compressor runs automatically in modes from ªmixº
to full defrost when outside temperatures are above
freezing.
²Air conditioning is available in any mode by
pressing the snowflake, A/C on/off button.
MANUAL THREE ZONE
FRONT CONTROL PANEL
²Primary control of the rear heater-A/C system is
on the instrument panel. This control allows the
driver to set the rear compartment fan speed, to turn
the rear heater-A/C system off, or to give control to
the intermediate seat occupants by switching to the
Rear position. When the rear heater-A/C system is
controlled from the instrument panel, rear air tem-
perature is based on the driver-side temperature con-
trol position, and the mode (floor or overhead air) is
based on the front control's mode position.
²The mode control knob enables continuously
variable proportioning of air flow between modes but
has detents adjacent to each icon.
²The blower control provides four separate speeds
and an Off position. When the heater-A/C system is
off, the HVAC computer closes the recirculation door
to prevent outside air from entering the passenger
compartment.
²Interior air may be recirculated to speed up
heating or cooling in all modes except defrost and
mix by pressing the Recirculate button on the control
panel.
²To reduce humidity for rapid defogging the A/C
compressor runs automatically in modes from ªmix'
to full defrost when outside temperatures are above
freezing.
²Air conditioning is available in any mode by
pressing the snowflake, A/C on/off, button.
REAR CONTROL PANEL
With the rear control active, temperature selection
dictates the air distribution mode (floor or overhead
air) of the rear unit: a cool temperature setting
directs flow to the overhead outlets and a warm tem-
perature setting to the floor.
AUTOMATIC TEMPERATURE CONTROL
Comfort temperature or perceived temperature is
affected by air flow, sun levels on exposed skin, etc.
The air temperature may be higher or lower than the
comfort temperature. The automatic temperature
control (ATC) system uses two infrared sensors in the
instrument panel center stack to measure the tem-
perature of the front occupants in order determine
their comfort level relative to their selected comfort
temperature. The integral HVAC computer adjusts
temperature and air flow rates to maintain the cus-
tomer-perceived comfort temperatures. The air tem-
perature in the passenger compartment may be
slightly higher or lower than the comfort tempera-
ture at any time. For instance, on sunny summer
days the air flow will probably be cooler than the
comfort temperature; on cold or cloudy days and at
night it will probably be slightly warmer.
The Three-Zone ATC system uses the infrared sen-
sors located in the instrument panel center stack
along with an offset calibration strategy to meet the
comfort requirements of the rear seat occupants.
FRONT CONTROL PANEL
²AUTO HI/LO± This system features two sets of
automatic control logic that allow either a rapid cool-
down rate or a somewhat slower cool-down rate with
less fan noise. HI-AUTO controls the system to reach
its assigned temperature quickly with a higher fan
speed. LO-AUTO controls the system to reach its
assigned temperature somewhat slower with less fan
noise. Both modes will automatically engage auto
recirculation.
²DEFROST± The defrost function must be man-
ually selected to direct air flow to the windshield to
remove fog or ice. The ATC system cannot automati-
cally sense the presence of fog or ice on the wind-
shield.
²RECIRC± The RECIRC button will close the
air inlet door. If the system is in auto recirc (indica-
tor being displayed automatically), pressing the man-
ual recirc button will disable the auto recirc function
until one of the auto keys are pressed or the ignition
is cycled. If Auto HI/LO is pressed while manual
recirc is active, manual recirc will be deactivated.
²REAR WINDOW DEFOGGER± Pushing the
button sends a PCI bus message to the intelligent
power module which controls the rear window defog-
ger and side view mirror (if equipped) circuitry. The
RSHEATING & AIR CONDITIONING24-5
HEATING & AIR CONDITIONING (Continued)

defogger function will be active for 10 minutes and
can be turned off by a switch press. The defogger will
function while the control is in the ON mode.
²FAN/MODE± The Fan and Mode knobs have
17 manual selectable positions. Manually changing
either of the rotary knobs for mode or fan speed set-
tings makes control of that blower motor manual. If
only one is changed manually, the other remains
under automatic control. Pressing the HI-AUTO/LO-
AUTO rocker switch restores full automatic control.
²BLOWER DELAY TIMER± The word DELAY
is displayed at start-up to signify that the system is
waiting so that cold air will not be blowing. This tells
the operator that it is unnecessary to turn the sys-
tem off, raise the temperature setting or turn the fan
speed setting down to prevent cold air from blowing.
A countdown in minutes and seconds until the engine
is warm enough to begin delivering heat to the pas-
sengers alternates with the DELAY message at 25
second intervals. This countdown is based on actual
measurement of the rate of engine coolant tempera-
ture change. During the delay time, mix mode is
selected and the fan operates at a low speed to keep
the windshield fog free.
²REAR CONTROL (Three-Zone only)± When
the Rear System control knob is moved to the OFF
position, there will be a delay of approximately 1 sec-
ond before the system actually turns off. This delay
is to prevent an undesired blower dropout if the knob
is moved through OFF to the other selections.
REAR CONTROL PANEL ± THREE ZONE ATC
SYSTEM
Primary control of the rear compartment heating-
A/C system for the Three-Zone ATC system is in the
instrument panel center stack. This control allows
the driver to turn the rear heating-A/C system off, or
allows the intermediate seat occupants control of the
rear system by switching to the REAR position, or
provides fully automatic control based on the temper-
ature setting shown on the front control display.
²REAR CONTROL± Selecting automatic control
of the rear unit at the instrument panel, illuminates
a Locked Padlock in the rear control panel display.
Selecting REAR activates the rear control panel and
the Padlock then appears unlocked.
²FAN KNOB± The rear fan control has Off and
AUTO positions and a range of manual speed set-
tings that override the AUTO setting.
²MODE KNOB± The mode control allows inter-
mediate seat occupants to manually override the
automatic mode and select any balance of air flow
between overhead and floor outlets from full over-
head to full floor.
²SET TEMP± The rear set temp control will
operate identical to the front controls. If the frontcontrol rear set temp button is pressed simulta-
neously with the rear control head, then the front
control head press events shall have priority, i.e. if
the front user presses Rear Set Temp down and the
rear user presses Set Temp up, then the rear set
temp will decrease.
DIAGNOSIS AND TESTING
A/C COOL DOWN TEST
The heater-A/C control module can perform an A/C
cool down test, which is a test performed during the
manufacturing process to confirm that the air condi-
tioning system is performing satisfactorily. This test
can also provide a quick confirmation of air condi-
tioning system performance to the service technician.
If the test is completed satisfactorily, no further ser-
vice is required. If the test is failed, proceed to the
A/C Performance Test to confirm the A/C system is
operating properly, or use a DRBIIItscan tool to
diagnose the A/C system control and distribution sys-
tems. Refer to the appropriate diagnostic informa-
tion.
MANUAL TEMPERATURE CONTROL
The front blower speed and rear blower speed (if
equipped with rear HVAC) must be set to High and
the evaporator temperature sensor must be greater
than 13É C (55É F) or the test will fail immediately.
The test is activated by depressing the A/C and Rear
Wipe/Wash buttons simultaneously and holding them
depressed for no less than five seconds. The Rear
Wipe/Wash and A/C LEDs will blink on and off until
the test is complete. If the LEDs stop blinking before
two minutes, then the cool down test has been com-
pleted successfully. If the two minutes expire without
the expansion valve temperature reaching -6É C (20É
F) less than the outside air temperature, then the
cool down test has been failed and further A/C sys-
tem diagnosis is required. If the test is failed, the
LEDs will continue to blink until the vehicle has
been driven for greater than 13 km (8 miles).
AUTOMATIC TEMPERATURE CONTROL
The ambient air temperature in the room where
the vehicle will be tested must be a minimum of 21É
C (70ÉF) for this test. The test is activated by
depressing the A/C and PWR buttons simultaneously
and holding them depressed for no less than four sec-
onds. The snowflake icon and the DELAY text in the
ATC display will blink on and off alternately until
the test is complete. If the snowflake icon and the
DELAY text stop blinking before two minutes, then
the cool down test has been completed successfully. If
the two minutes expire without the evaporator tem-
perature reaching -6É C (20É F) less than the evapo-
24 - 6 HEATING & AIR CONDITIONINGRS
HEATING & AIR CONDITIONING (Continued)

REMOVAL
(1) Disconnect and isolate the negative battery
cable.
(2) Remove the cover from the integrated power
module (IPM) (Fig. 8).
NOTE: Refer to the fuse and relay map on the inner
surface of the cover of the IPM for A/C compressor
clutch relay identification and location.
(3) Remove the A/C compressor clutch 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 A/C compressor clutch relay identification
and location.
(1) Position the A/C compressor clutch relay into
the proper receptacle in the IPM.
(2) Align the A/C compressor clutch relay termi-
nals with the terminal cavities in the IPM receptacle.
(3) Push down firmly on the A/C compressor clutch
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.
A/C HEATER CONTROL
DESCRIPTION
The A/C-heater control is located at the center of
the instrument panel and uses electrical controls.
These controls provide the vehicle operator with a
number of setting options to help control the climate
and comfort within the vehicle. Refer to the owner's
manual in the vehicle glove box for more information
on the suggested operation and use of these controls.
The A/C-heater control cannot be repaired. If faulty
or damaged, the entire unit must be replaced. The
control knobs are available for service replacement.
STANDARD PROCEDURE
A/C-HEATER CONTROL CALIBRATION
The A/C-heater control module must be recali-
brated each time an actuator motor or the control
module is replaced. If the vehicle is so equipped, the
calibration procedure also includes rear HVAC posi-
tions for each actuator motor.
(1) Turn the ignition switch to the On position.
(2) If equipped with the manual temperature con-
trol (MTC) system, press and hold the Rear Wipe/
Wash and Recirculation buttoms for at least five
seconds. If equipped with the automatic temperature
control (ATC) systen, simultaneously press and hold
the Power and Recirculation buttons on the A/C-
heater control for at least five seconds. The MTC
A/C-heater control Rear Wipe/Wash Light Emitting
Diode (LED) and Recirculation LED, or the ATC A/C-
heater control Delay and Recirculation graphics will
begin to flash when the calibration procedure has
begun.
(3) The calibration procedure should take less than
two minutes to complete for the manual A/C-heater
control, and less than twenty seconds for the ATC
A/C-heater control. When the LEDs or graphics stop
flashing, the calibration procedure is complete.
(4) If the LEDs or graphics continue to flash
beyond the two minute (manual) or twenty second
(ATC) calibration time, it indicates that the A/C-
heater control has detected a failure and a Diagnostic
Trouble Code (DTC) has been set. Refer to Body
Diagnostic Procedures to perform further diagnosis.
The LEDs or graphics will continue to flash even
after the ignition switch is cycled Off and On, until a
successful calibration is completed or until the vehi-
cle has been driven about 13 kilometers (8 miles).
Fig. 8 A/C Compressor Clutch Relay
1 - INTEGRATED POWER MODULE (IPM)
2 - A/C COMPRESSOR CLUTCH RELAY
3 - FRONT CONTROL MODULE
RSCONTROLS - FRONT24-19
A/C COMPRESSOR CLUTCH RELAY (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

(3) Connect the HVAC wire harness connector to
the blend 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 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).
BLOWER MOTOR RELAY
DESCRIPTION
The front blower motor relay is an International
Standards Organization (ISO)-type relay (Fig. 12).
Relays conforming to the ISO specifications have
common physical dimensions, current capacities, ter-
minal patterns, and terminal functions. The front
blower motor relay is located in the integrated power
module (IPM) in the engine compartment. See the
fuse and relay map on the inner surface of the cover
of the IPM for front blower motor relay identification
and location.
The black, molded plastic case is the most visible
component of the front blower motor relay. Five male
spade-type terminals extend from the bottom of the
base to connect the relay to the vehicle electrical sys-
tem, and the ISO designation for each terminal ismolded into the base adjacent to each terminal. The
ISO terminal designations are as follows:
²30 (Common Feed)- This terminal is con-
nected to the movable contact point of the relay.
²85 (Coil Ground)- This terminal is connected
to the ground feed side of the relay control coil.
²86 (Coil Battery)- This terminal is connected
to the battery feed side of the relay control coil.
²87 (Normally Open)- This terminal is con-
nected to the normally open fixed contact point of the
relay.
²87A (Normally Closed)- This terminal is con-
nected to the normally closed fixed contact point of
the relay.
The front blower motor relay cannot be adjusted or
repaired. If the relay is damaged or faulty, it must be
replaced.
OPERATION
The blower motor relay is an electromechanical
switch that uses a low current input from the Front
Control Module (FCM) to control the high current
output to the blower motor resistor (manual heater-
A/C control) or blower power module (ATC control).
The movable common feed contact point is held
against the fixed normally closed contact point by
spring pressure. When the relay coil is energized, an
electromagnetic field is produced by the coil wind-
ings. This electromagnetic field draws the movable
relay contact point away from the fixed normally
closed contact point, and holds it against the fixed
normally open contact point. When the relay coil is
de-energized, spring pressure returns the movable
contact point back against the fixed normally closed
contact point. The resistor or diode is connected in
parallel with the relay coil in the relay, and helps to
dissipate voltage spikes and electromagnetic interfer-
ence that can be generated as the electromagnetic
field of the relay coil collapses.
Fig. 11 Blend Door Actuator - LHD Shown, RHD
Typical
1 - WIRE HARNESS CONNECTOR
2 - MODE DOOR ACTUATOR
3 - SCREW (2)
4 - DRIVER BLEND DOOR ACTUATOR (DUAL-ZONE)
5 - HEATER CORE
6 - BLEND DOOR ACTUATOR (SINGLE ZONE) OR PASSENGER
BLEND DOOR ACTUATOR (DUAL-ZONE)
Fig. 12 Front Blower Motor Relay
RSCONTROLS - FRONT24-23
BLEND DOOR ACTUATOR (Continued)