Chrysler Town, Dodge Caravan. Manual - part 506

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 DRBIII

t scan

tool. Refer to the appropriate diagnostic information.

MODE DOOR ACTUATOR

DESCRIPTION

The mode door actuator is a reversible, 12-volt

Direct Current (DC), servo motor (Fig. 20). The sin-
gle mode door actuator is located on the driver side
end of the heater-A/C housing unit, close to the top of
the distribution housing. The mode door actuator is
mechanically connected to the mode door. The mode
door actuator is interchangeable with the actuators

for the blend air door(s) and the recirculation air
door. Each actuator 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 heater-A/C unit housing. Each actuator also has
an identical output shaft with splines that connects
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

Fig. 19 Infrared Temperature Sensor

1 - INSTRUMENT PANEL CENTER BEZEL
2 - CENTER BEZEL OUTLETS
3 - INFRARED TEMPERATURE SENSOR

Fig. 20 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)

24 - 24

CONTROLS - FRONT

INFRARED TEMPERATURE SENSOR (Continued)

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 DRBIII

t scan 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

(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.

(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

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)

CONTROLS - FRONT

24 - 25

MODE DOOR ACTUATOR (Continued)

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 housing
and 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 DRBIII

scan tool. Refer to the appropriate diagnostic infor-
mation.

REMOVAL

(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 power module from the module con-
nector receptacle.

(5) Reach through the glove box opening to access

and disconnect the blower motor pigtail wire connec-
tor from the power module connector receptacle.

(6) Remove the two screws that secure the power

module to the evaporator housing.

(7) Remove the power module from the evaporator

housing.

INSTALLATION

(1) Position the power module into the evaporator

housing.

Fig. 22 Power Module

1 - POWER MODULE
2 - LOWER GLOVE BOX OPENING REINFORCEMENT
3 - EVAPORATOR HOUSING

24 - 26

CONTROLS - FRONT

POWER MODULE (Continued)

(2) Install and tighten the two screws that secure

the power module to the evaporator housing. Tighten
the screws to 2 N·m (18 in. lbs.).

(3) Reconnect the blower motor pigtail wire con-

nector to the power module connector receptacle.

(4) Reconnect the instrument panel wire harness

connector for the power module to the module con-
nector 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.

RECIRCULATION DOOR
ACTUATOR

DESCRIPTION

The recirculation door actuator is a reversible,

12-volt Direct Current (DC), servo motor (Fig. 23).
The single recirculation door actuator is located on
the passenger side end of the heater-A/C housing
unit, on the bottom of the lower intake air housing.
The recirculation door actuator is mechanically con-
nected to the recirculation air door. The recirculation
door actuator is interchangeable with the actuators
for the blend air door(s) and the mode door. Each
actuator is contained within an identical black
molded plastic housing with an integral wire connec-
tor receptacle. Two integral mounting tabs allow the
actuator to be secured with two screws to the lower
intake air housing. Each actuator also has an identi-

cal output shaft with splines that connects it to the
linkage that drives the recirculation air door. The
recirculation door actuator does not require mechan-
ical indexing to the recirculation air door, as it is
electronically calibrated by the heater-A/C control
module. The recirculation door actuator cannot be
adjusted or repaired and, if damaged or faulty, it
must be replaced.

OPERATION

The recirculation door actuator is connected to the

heater-A/C control module through the vehicle elec-
trical system by a dedicated two-wire take out and
connector of the HVAC wire harness. The recircula-
tion door actuator can move the recirculation door in
two directions. When the heater-A/C control module
pulls the voltage on one side of the motor connection
high and the other connection low, the recirculation
air door will move in one direction. When the module
reverses the polarity of the voltage to the motor, the
recirculation air door moves in the opposite direction.
When the module makes the voltage to both connec-
tions high or both connections low, the recirculation
air door stops and will not move. These same motor
connections also provide a feedback signal to the
heater-A/C control module. This feedback signal
allows the module to monitor the operation and rela-
tive position of the recirculation door actuator and
the recirculation air door. The heater-A/C control
module learns the recirculation air door stop posi-
tions during the calibration procedure and will store
a Diagnostic Trouble Code (DTC) for any problems it
detects in the recirculation door actuator circuits.
The recirculation door actuator can be diagnosed
using a DRBIII

t scan tool. Refer to the appropriate

diagnostic information.

REMOVAL

(1) Disconnect and isolate the battery negative

cable.

Fig. 23 Recirculation Door Actuator

1 - LOWER INTAKE AIR HOUSING
2 - RECIRCULATION DOOR ACTUATOR
3 - HVAC WIRE HARNESS
4 - SCREW (2)
5 - LOWER EVAPORATOR HOUSING

CONTROLS - FRONT

24 - 27

POWER MODULE (Continued)

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