2001 CHRYSLER VOYAGER heater

TABLE OF CONTENTS - Continued
RIGHT SLIDING DOOR CONTROL MODULE C1 (POWER SLIDING DOOR) - BLACK
8 WAY ..............................................................1082
RIGHT SLIDING DOOR CONTROL MODULE C2 (POWER SLIDING DOOR) -
BLACK/RED 20 WAY..................................................1082
RIGHT SLIDING DOOR LATCH SENSING SWITCH (POWER SLIDING DOOR) -
BLACK 6 WAY........................................................1082
RIGHT SLIDING DOOR LOCK MOTOR (POWER SLIDING DOOR) - BLACK 4
WAY................................................................1083
RIGHT SLIDING DOOR LOCK MOTOR/AJAR SWITCH (MANUAL SLIDING DOOR) -
BLACK 4 WAY........................................................1083
RIGHT SLIDING DOOR MOTOR (POWER SLIDING DOOR) - BLACK 8 WAY. . . .1083
SENTRY KEY IMMOBILIZER MODULE - BLACK 6 WAY.....................1083
SIREN (UNITED KINGDOM) - BLACK 4 WAY..............................1083
THATCHAM ALARM MODULE C1 (UNITED KINGDOM) - BLACK 16 WAY.......1084
THATCHAM ALARM MODULE C2 (UNITED KINGDOM) - WHITE 4 WAY........1084
TRANSMISSION CONTROL MODULE (EATX) - BLACK 60 WAY..............1085
TXV SOLENOID (ATC)-2WAY.........................................1086
10.0 SCHEMATIC DIAGRAMS...............................................1087
10.1AIRBAG SYSTEM................................................1087
10.2AUDIO SYSTEM.................................................1088
10.2.1PREMIUM.............................................1088
10.2.2BASE.................................................1089
10.2.3CD CHANGER.........................................1090
10.2.4REMOTE RADIO CONTROLS.............................1091
10.3CABIN HEATER.................................................1092
10.4AUTOMATIC TEMPERATURE CONTROL SYSTEM....................1093
10.4.1FRONT ATC............................................1093
10.4.2REAR ATC.............................................1094
10.5COMMUNICATION...............................................1095
10.5.1PCM COMMUNICATION.................................1096
10.5.2ECM & CABIN HEATER ASSIST COMMUNICATION - DIESEL
ONLY.................................................1096
10.6DOOR AJAR WITH POWER SLIDING DOORS........................1097
10.7DOOR AJAR WITHOUT POWER SLIDING DOORS....................1098
10.8EXTERIOR LIGHTING............................................1099
10.9IGNITION SWITCH...............................................1100
10.10INSTRUMENT CLUSTER Ð BASE..................................1101
10.11INSTRUMENT CLUSTER & MESSAGE CENTER......................1102
10.12INTELLIGENT POWER MODULE/BODY CONTROL MODULE POWER AND
GROUNDS......................................................1103
10.13INTERIOR LIGHTING.............................................1104
10.14MANUAL TEMPERATURE CONTROLS..............................1105
10.14.1BASE MANUAL TEMPERATURE CONTROL SYSTEM LHD.....1105
10.14.2BASE MANUAL TEMPERATURE CONTROL SYSTEM RHD....1106
10.14.3DUAL-ZONE MANUAL TEMPERATURE CONTROL SYSTEM
LHD ..................................................1107
10.14.4DUAL-ZONE MANUAL TEMPERATURE CONTROL SYSTEM
RHD..................................................1108
10.14.5BLOWER MOTOR.......................................1109
10.15MEMORY SYSTEM...............................................1110
10.16OVERHEAD CONSOLE...........................................1111
xxiv

1.0 INTRODUCTION
The procedures contained in this manual include
all the specifications, instructions and graphics
needed to diagnose 2001 body system problems. The
diagnostics in this manual are based on the failure
condition or symptom being present at the time of
diagnosis.
Please follow the recommendations below when
choosing your diagnostic path.
1. First make sure the DRBIIItis communicating
with the appropriate modules; i.e., if the
DRBIIItdisplays a ªNo Responseº or a ªBus6
Signals Openº condition, you must diagnose that
first.
2. Read DTC's (diagnostic trouble codes) with the
DRBIIIt.
3. If no DTC's are present, identify the customer
complaint.
4. Once the DTC or customer complaint is identi-
fied, locate the matching test in the Table of
Contents and begin to diagnose the symptom.
All component location views are in Section 8.0. All
connector pinouts are in Section 9.0. All schematics
are in Section 10.0. All Charts and Graphs are in
Section 11.0.
An * placed before the symptom description indi-
cated a customer complaint.
When repairs are required, refer to the appropri-
ate service information for the proper removal and
repair procedure.
Diagnostic procedures change every year. New
diagnostic systems may be added: carryover systems
may be enhanced. READ THIS MANUAL BEFORE
TRYING TO DIAGNOSE A VEHICLE DIAGNOS-
TIC TROUBLE CODE. It is recommended that you
review the entire manual to become familiar with all
the new and changed diagnostic procedures.
This book reflects many suggested changes from
readers of past issues. After using this book, if you
have any comments or suggestions, please fill out
the form in the back of this book and mail it back to
us.
1.1 SYSTEM COVERAGE
This diagnostic procedures manual covers all
2001 Chrysler Voyager and Caravan vehicles. This
diagnostic procedures manual also covers both left
hand drive (LHD) and right hand drive (RHD)
vehicles. There may be some slight differences in
the location views of components. If the location
views shown are on a LHD vehicle, a RHD vehicle
will be symmetrically opposite.
1.2 SIX-STEP TROUBLESHOOTING
PROCEDURE
Diagnosis of the body system is done in six basic
steps:
²verification of complaint
²verification of any related symptoms
²symptom analysis
²problem isolation
²repair of isolated problem
²verification of proper operation
2.0 IDENTIFICATION OF
SYSTEM
The vehicle systems that are part of the ªbodyº
system are:
²Airbag
²Audio
²Cabin Heater
²Chime
²Communication
²Door Ajar System
²Electrically heated system
²Exterior lighting
²Heating and A/C
²Instrument Cluster
²Interior Lighting
²Manual Temperature Control
²Memory Seat
²Overhead Console
²Power Door Lock/RKE
²Power Folding Mirrors
²Power Sliding Doors
²Power Liftgate
²Power windows
²Vehicle Theft Security System (VTSS)
²Windshield Wiper and Washer
3.0 SYSTEM DESCRIPTION AND
FUNCTIONAL OPERATION
The body system on the 2001 RG consists of a
combination of modules that communicate over the
PCI bus (Programmable Communication Interface
multiplex system). Through the PCI bus, informa-
tion about the operation of vehicle components and
circuits is relayed quickly to the appropriate mod-
ule(s). All modules receive all the information trans-
1
GENERAL INFORMATION

3.5 COMMUNICATION
The Programmable Communication Interface or
PCI Bus is a single wire multiplexed network capa-
ble of supporting binary encoded messages shared
between multiple modules. The PCI bus circuit is
identified as D25 and is white with a violet tracer.
Additional tracer colors may be added to the violet
in order to distinguish between different module
connections. The modules are wired in parallel.
Connections are made in the harness using splices.
One splice called the Diagnostic Junction Port,
serves as the ªHubº of the bus. The Diagnostic
Junction Port provides an access point to isolate
most of the modules on the bus in order to assist in
diagnosing the circuit. The following modules are
used on the RG:
²Body Control Module
²Front Control Module
²Occupant Restraint Controller
²Left Side Impact Airbag Control Module
²Right Side Impact Airbag Control Module
²Controller Antilock Brake
²Powertrain Control Module
²Engine Control Module - Diesel Only
²Radio
²CD Changer
²Transmission Control Module
²Automatic Temperature Control Module
²A/C Heater Control Module (MTC)
²Sentry Key Immobilizer Module
²RKE/Thatcham Alarm Module
²Memory Seat/Mirror Module
²Overhead Console
²Mechanical Instrument Cluster
²Left Sliding Door Control Module
²Right Sliding Door Control Module
²Power Liftgate Module
Each module provides its own bias and termina-
tion in order to transmit and receive messages. The
bus voltage is at zero volts when no modules are
transmitting and is pulled up to about seven and a
half volts when modules are transmitting.
The bus messages are transmitted at a rate
averaging 10800 bits per second. Since there is only
voltage present when the modules transmit and the
message length is only about 500 milliseconds, it is
ineffective to try and measure the bus activity witha conventional voltmeter. The preferred method is
to use the DRBIIItlab scope. The 12v square wave
selection on the 20-volt scale provides a good view of
the bus activity. Voltage on the bus should pulse
between zero and about seven and a half volts.
Refer to the following figure for some typical dis-
plays.
The PCI Bus failure modes are broken down into
two categories. Complete PCI Bus Communication
Failure and individual module no response. Causes
of complete PCI Bus Communication Failure in-
clude a short to ground or battery on the PCI
circuit. Individual module no response can be
caused by an open circuit at either the Diagnostic
Junction Port or the module, or an open battery or
ground circuit to the affected module.
Symptoms of a complete PCI Bus Communication
Failure would include but are not limited to:
²All gauges on the MIC stay at zero
²All telltales on MIC illuminate
²MIC backlighting at full intensity
²Dashed lines in the overhead console ambient
temperature display
²No response received from any module on the PCI
bus (except the PCM)
²No start (if equipped with Sentry Key Immobi-
lizer)
Symptoms of Individual module failure could
include any one or more of the above. The difference
would be that at least one or more modules would
respond to the DRBIIIt.
Diagnosis starts with symptom identification. If a
complete PCI Bus Communication Failure is sus-
pected, begin by identifying which modules the
vehicle is equipped with and then attempt to get a
response from the modules with the DRBIIIt.Ifany
modules are responding, the failure is not related to
the total bus, but can be caused by one or more
modules PCI circuit or power supply and ground
circuits. The DRBIIItmay display ªBUS +/- SIG-
NAL OPENº or ªNO RESPONSEº to indicate a
communication problem. These same messages will
be displayed if the vehicle is not equipped with that
particular module. The CCD error message is a
default message used by the DRBIIItand in no way
indicates whether or not the PCI bus is operational.
The message is only an indication that a module is
either not responding or the vehicle is not equipped.
11
GENERAL INFORMATION

3.7.6 EXTERIOR LIGHTING BATTERY
SAVER
The BCM monitors the status of, and controls, the
Park Lamps, Headlamps and Fog Lamp relays. If
any exterior lamps are left ON after the ignition is
turned OFF, the BCM will turn them OFF after 3
minutes.
3.7.7 AUTO HEADLAMPS
This feature is available on vehicles equipped
with both the Electrocromatic Mirror (ECM) and
the Compass/Mini-Trip Computer (CMTC). When
the BCM detects a day/night signal from the CMTC,
an ECM is present and Auto Headlamp mode is
selected.
3.8 FRONT CONTROL MODULE
The Front Control Module (FCM) is an electrical
control and interface center located in the engine
compartment. When it is mated to the Power Dis-
tribution Center (PDC), it is referred to as the
Intelligent Power Module (IPM). The IPM, with its
fuses and relays provides power and signal distri-
bution throughout most of the vehicle. The FCM
receives both hard wire and digital electronic inputs
from the vehicle electrical system through the PDC.
Based on these inputs and the ignition switch
position, it provides direct power feeds and relay
control to some of the vehicles' most critical electri-
cal systems.
The Front Control Module provides the following
features:
Controlled power feeds:
²Front airbag system
²Side airbag system
²Headlamp power
²EATX module power (4 speed only)
²Front washer motor
²Rear washer motor
²Brake shift interlock system
Relay controls:
²Fog lamp relay (when equipped)
²Park lamp relay
²Front wiper on relay
²Front wiper high/low relay
²Accessory relay
²Horn relay
²Front & rear blower relay
²Name brand speakers (NBS) relay
²Electronic back light (EBL) run only relay
²Cabin heater relayElectrical inputs:
²Headlamp battery supplies1&2
²Module battery supply
²Power ground
²Ignition switch RUN or START position status
²Ignition switch START only status
²PCI Bus
²Stop lamp switch
²Horn switch
²Back-up switch
²Wiper park switch
²Washer fluid level switch
²Brake fluid level switch
²Ambient temperature sensor
²Right park lamp outage
²Left park lamp outage
²Battery IOD
²Battery (+) connection detection
²Flash reprogramming voltage
3.8.1 CONTROLLED POWER FEEDS
Front airbag system
The FCM provides power to the Occupant Re-
straint Control (ORC) system through two ªfuse-
lessº circuits (ORC RUN/START, and ORC RUN
only). These circuits are electronically controlled
and continuously monitored for malfunctions.
Power is supplied while the ignition switch is in the
RUN and START positions on pin 48 of the FCM
connector, and in the RUN only position on pin 29.
Side airbag system
The FCM provides power to the Side Impact
Airbag Control Module (SIACM) system through
one ªfuselessº circuit. This circuit is electronically
controlled and continuously monitored for malfunc-
tions. Power is supplied in the ignition RUN and
START positions on pin 28 of the FCM connector.
Headlamp power
The headlamp switch is a direct input to the
BCM. The BCM sends a PCI Bus message to the
FCM informing it of a headlamp switch status
change. The FCM then turns on power to the
headlamps through four ªfuselessº circuits. These
circuits are electronically controlled and continu-
ously monitored for malfunctions. Power is supplied
to each filament in a separate circuit (RH low on pin
6, RH high on pin 4, LH low on pin 3 and LH high
on pin 5). For vehicles equipped with Daytime
Running Lamps (DRL), the FCM electronically
steps down the headlamp voltage to provide the
desired illumination.
13
GENERAL INFORMATION

Front and rear blower relay
The blower control switch is part of the Automatic
Temperature Control (ATC) or A/C-Heater Control
Module, (Manual Temp). When the blower switch is
turned on, the ATC or A/C-Heater Control Module
sends a PCI Bus message to the FCM. The front and
rear blower relay is then powered through low side
control on pin 30 of the FCM. The relay provides the
high side to the blower motor, and the blower speed
is governed through low side control in the ATC or
A/C-Heater Control Module. This circuit is electron-
ically controlled and continuously monitored for
malfunctions.
Name Brand Speakers (NBS) relay
The NBS relay operates through the vehicle bus
interface between the radio and the FCM. When the
radio is turned on, the radio sends a PCI Bus
message to the FCM. The NBS relay is then pow-
ered on through low side control on pin 11 of the
FCM. The relay supplies power to the amplified
speaker, and ground is supplied through the radio.
This circuit is electronically controlled and contin-
uously monitored for malfunctions.
Electronic Back Light (EBL) relay
The rear defrost switch is part of the Automatic
Temperature Control or A/C-Heater Control Module
(Manual Temp). When the ignition switch is in the
RUN position and the rear defrost switch is turned
on, the ATC or A/C-Heater Control Module sends a
PCI Bus message to the FCM. The EBL run only
relay is then powered through low side control on
pin 31 of the FCM. The relay provides the high side
to the rear window defrost grid, and ground is
attached to the vehicle body. The FCM will only
allow the rear defrost to operate in the RUN posi-
tion. This circuit is electronically controlled and
continuously monitored for malfunctions.
Cabin Heater Relay
When the ignition is in Run, the FCM monitors
the PCI bus for the Cabin Heater Activation re-
quest. The A/C ± Heater Control Module initiates
this request only when all conditions for Cabin
Heater activation are favorable. The request carries
the status bit that the FCM requires to activate its
Cabin Heater Assist Control output. This output is
a low side driver (coming from FCM pin 15) which
supplies a ground signal to the Cabin Heater (pin
5). When the Cabin Heater receives this ground
signal input, it interprets this as an activation
signal. The FCM low side driver is also capable of
diagnostic sensing. The driver will sense an open
circuit when the driver is off, and will sense a short
to voltage when the driver is on. The FCM will set
DTCs for both of these types of faults. For addi-
tional information, refer to Cabin Heater under
General Information and Diagnostic Procedures in
the manual.3.8.3 ELECTRICAL INPUTS
Headlamp battery supplies1&2Ð12 volt
input on pins 1 and 2. Battery supply voltage for
switching headlamp circuits only.
Module battery supply Ð12 volt input on pin 9.
Battery supply voltage for all other FCM opera-
tions.
Power ground ÐGround source on pin 8 for all
FCM operations.
Ignition switch RUN or START position status
Ð12 volt input on pin 37. Allows the FCM to
determine the ignition switch status for related
FCM operations.
Ignition switch START only status Ð12 volt
input on pin 19. Allows the FCM to discriminate
between RUN/START input and START for related
FCM operations.
PCI Bus ÐApproximately 7.5 volt input on pin 22.
Allows the FCM to communicate with other mod-
ules on the vehicle bus.
Stop lamp Switch status Ð12 volt input on pin
44. Provides for brake shift interlock function.
Horn Switch ÐGround input on pin 17. Primary
means for engaging the horn.
Back-up switch ÐGround input on pin 39. Input
is converted to a PCI Bus status message for use by
other modules.
Wiper park switch ÐGround input on pin 16.
Used to determine park placement of wipers. Also
used as feedback to FCM to determine correct
operating mode of wipers.
Washer fluid level switch ÐGround input to
pull-up on pin 18. Ground is switched into the
circuit when washer bottle fluid level is low.
Brake fluid level switch ÐGround input to
pull-up on pin 36. Ground is switched into the
circuit when brake fluid level is low.
Ambient temperature sensor ÐResistive input
to pull-up on pin 25. Corresponding voltage level is
converted to a PCI Bus message for use by other
modules on the bus.
Right park lamp outage Ð12 volt input on pin
21. Used to determine if right park lamp circuit is
operating properly.
Left park lamp outage Ð12 volt input on pin 41.
Used to determine if left park lamp circuit is
operating properly.
Battery IOD Ð12 volt input on pin 20. The FCM
enters a low power consumption mode when the
ignition is turned OFF. This low current draw
battery supply keeps the microprocessor function-
ing in the low power mode.
Battery (+) connection detection Ð12 volt
input on pin 38. The battery connection on the PDC
incorporates the use of an internal switch to deter-
mine if the connector is properly mated and the
Connector Positive Assurance (CPA) is engaged. If
15
GENERAL INFORMATION

the CPA is not properly engaged, a voltage on pin 38
will be interpreted as an unseated connector and a
fault will set.
Flash programming voltage Ð20 volt input on
pin 42. When a DRBIIItis connected and the
proper flash reprogramming sequence is selected,
the 20 volt signal will be applied through pin 42.
3.9 HEATING & A/C
3.9.1 AUTOMATIC TEMPERATURE
CONTROL (ATC)
3.9.1.1 CABIN HEATER
For vehicles equipped with a diesel engine, a
Cabin Heater is used in conjunction with the HVAC
system. The Cabin Heater is designed to supply the
vehicle's occupants with heat prior to the engine
reaching operating temperature. For additional in-
formation on this system, refer to Cabin Heater
under General Information and Diagnostic Proce-
dures in this manual.
3.9.1.2 SYSTEM OPERATION
The Automatic Temperature Control (ATC) sys-
tem provides fully adjustable three zone climate
control; Driver front zone, Passenger Front zone
and Rear zone. The following is a list of ATC
controls and features:
± a POWER button which allows the operator to
turn the system completely off.
± AUTO HIGH/LOW switch allows the operator
to select what rate (fan speed) the system will
provide the selected comfort level.
± DRIVER, REAR and PASSENGER rocker
switches to select desired temperature for each
zone.
± Recirculation button allows cooling air to be
recirculated which maximizes cooling ability.
± A/C select button allows the operator to turn
the A/C compressor off.
± Defroster button allows the operator to turn on
the defroster independently during automatic
control.
± Fan control rotary switch for selecting fan
speed.
± Mode rotary switch for selecting heating/
cooling direction.
± REAR SYSTEM rotary switch for activating
the Rear ATC Switch allowing intermediate
passenger control over rear climate control.
3.9.1.3 BLOWER MOTOR OPERATION
The Automatic Temperature Control (ATC) front
and rear blower control provides continuously vari-
able control of air flow rate to meet occupant
comfort requirements. Pulse width modulation of
the blower motor power allows the front and rear
blower to operate at any speed from off to full speed.
When front or rear blower operation is required, the
ATC sends a PCI Bus message to the Front Control
Module (FCM) requesting blower relay ON. The
FCM provides a ground for the front and rear
blower motor relay coils, activating both relays. The
front and rear blower relays provide 12 volts to
their respective blower motor power modules. Each
module provides a 12 volt blower motor control
signal to the ATC. The ATC provides a pulse width
modulated (duty-cycle) ground signal to this circuit
based on climate requirements. The higher voltage
on the signal circuit (less duty-cycle ground) the
lower the blower speed request. The lower voltage
on the signal circuit (more duty-cycle ground) the
higher the blower speed request.
3.9.1.4 INFRARED SENSORS
The ATC system uses infrared (I/R) sensors to
monitor and control oocupant comfort levels. This
sensing system replaces interior air temperature
and solar sensors which required complex control
programs to maintain occupant comfort levels. The
front I/R sensor is located in the instrument panel
center bezel outlet. The rear I/R sensor is located in
the rear overhead mounted ATC switch.
3.9.1.5 REAR ATC SWITCH
The rear ATC switch is mounted in the headliner.
The switch contains a rotary adjustment for fan
speed, a rotary adjustment for mode selection, a
push button switch for temperature selection and a
digital display of the selected temperature.
3.9.1.6 COOLDOWN TESTING
The ATC provides a feature referred to as a
Cooldown Test. This test is initiated using the
DRBIIItand is designed to check the performance
of the air conditioning system. The ATC will not
perform this test if the ambient air temperature is
below 12ÉC (53ÉF). During the test, the ATC com-
pares the ambient air temperature to the evapora-
tor temperature sensor. To pass the cooldown test,
the evap temperature sensor must drop -6ÉC (20ÉF)
below ambient temperature within 2 minutes of
start of test. At the completion of the cooldown test
the DRBIIItwill display one of the following mes-
sages indicating test outcome:
± Cooldown Test Passed
± Cooldown Test Failed
16
GENERAL INFORMATION

± Evap Temp Sensor Shorted
± Evap Temp Sensor Open
± A/C Pressure Too Low
± A/C Pressure Too High
± Invalid Conditions for Cooldown Test, Evap
Temperature Too Low
If a message other than Cooldown Test Passed
occurs, refer to the appropriate symptom for diag-
nosis.
3.9.1.7 ACTIVE AND STORED TROUBLE
CODES
The Automatic Temperature Control (ATC) is
capable of storing Active and Stored trouble codes.
Active codes indicate a current fault in the system.
Stored codes indicate that a problem has occurred
in the system, however is not currently present.
Active codes cannot be erased until the problem
causing the code has been repaired. At this time the
Active code is converted to a Stored code, which can
be erased using the DRBIIIt.
3.9.2 MANUAL TEMPERATURE CONTROL
3.9.2.1 SYSTEM AVAILABILITY
Depending on the model, either a Single-Zone Air
Conditioning System or a Dual-Zone Air Condition-
ing System is currently available in these vehicles.
3.9.2.2 CABIN HEATER
For Vehicles equipped with a diesel engine, a
Cabin Heater is used in conjunction with the HVAC
system. The Cabin Heater is designed to supply the
vehicle's occupants with heat prior to the engine
reaching operating temperature. For additional in-
formation on this system, refer to Cabin Heater
under General Information and Diagnostic Proce-
dures in this manual.
3.9.2.3 ZONE CONTROL ± SINGLE-ZONE
The Single-Zone Air Conditioning System main-
tains incoming air temperature, airflow, fan speed,
and fresh air intake for the entire vehicle from the
instrument panel mounted A/C ± Heater Control
Module. The full range of temperature that the
system can produce in any mode for the entire
vehicle is available by positioning the blend control
to the desired range.
3.9.2.4 ZONE CONTROL ± DUAL-ZONE
The Dual-Zone Air Conditioning System main-
tains incoming air temperature, airflow, fan speed,
and fresh air intake for the entire vehicle from the
instrument panel mounted A/C ± Heater ControlModule. In addition, this system provides com-
pletely independent side-to-side control of incoming
air temperature. The full range of temperature that
the system can produce in any mode is available on
either side of the vehicle by positioning the inde-
pendent driver and passenger blend controls to the
desired range.
3.9.2.5 AIR DISTRIBUTION
The HVAC unit has five fully adjustable instru-
ment panel outlets. Side-window demister outlets
in the instrument panel eliminate door ducts and
door-to-instrument panel seals. A single, central
mounted outlet delivers air for defrosting the wind-
shield. Air exhausters allow air entering at the
front of the vehicle to flow out the back to the rear
occupants. Mid-cabin comfort control directs only
cooling air flow to the intermediate seat occupants
through outlets at the rear of each front door trim
panel. Air is supplied to these outlets from the
instrument panel through ducts in the doors that
use molded seals at the instrument panel to prevent
air leakage. Wide outlets under the front seats with
directional dividers distribute heated air across the
floor to the intermediate seat occupants. Ducts in
the center of the vehicle under the carpet deliver air
from the HVAC unit to these outlets. Models
equipped with Dual-Zone A/C systems also include
a dust and odor air filter installed in the HAVC
housing.
3.9.2.6 DOOR ACTUATORS
The electric door actuators are a two-wire design.
Each door actuator uses a similar connector wired
directly to the A/C ± Heater Control Module. Single-
Zone systems have one blend door actuator, one
mode door actuator, and one recirculation door
actuator. Dual-Zone systems have two blend door
actuators, one mode door actuator, and one recircu-
lation door actuator. All of the door actuators are
accessible from the vehicle's interior.
3.9.2.7 DOOR ACTUATOR CONTROL
The A/C ± Heater Control Module knows the
number of operating actuator revolutions required
for full door travel as well as the number of actuator
commutator pulses per revolution. Using these pa-
rameters, the A/C ± Heater Control Module runs
the actuator for the number of commutator pulses
that correspond to the desired door position. To
maintain accuracy, the system recalibrates itself
periodically at known zero and full travel condi-
tions.
17
GENERAL INFORMATION

3.9.2.8 HVAC SYSTEM RELAYS
The Integrated Power Module (IPM) houses and
provides power to the A/C Clutch Relay and Front
Blower Motor Relay.
3.9.2.9 EVAPORATOR TEMPERATURE
SENSOR
An evaporator temperature sensor, located on the
A/C expansion valve under the hood, replaces the
previously used fin sensor.
3.9.2.10 A/C ± HEATER CONTROL
MODULE, SWITCH OPERATION
Power Switch
The Power Switch is a momentary contact switch.
The switch LED illuminates when the switch is on.
The Power Switch setting is remembered during
power down.
Rear Window Defogger Switch
The Rear Window Defogger Switch is a momen-
tary contact switch. Toggling the switch results in
the A/C ± Heater Control Module sending a change
of state message to the FCM to provide rear window
defogger activation or deactivation respectively.
The switch LED illuminates when the switch is on.
Recirculation Switch
The Recirculation Switch is a momentary contact
switch. Toggling the switch on results in the A/C ±
Heater Control Module signaling the actuator to
close the fresh-air door. Toggling the switch off
results in the A/C ± Heater Control Module signal-
ing the actuator to open the fresh-air door. The
switch LED illuminates when the switch is on.
When the Power Switch is off, the A/C ± Heater
Control Module closes the fresh-air door to prevent
outside air from entering the passenger compart-
ment. The recirculation mode will cancel whenever
defrost is requested. Pressing the Recirculation
Switch while in defrost mode will illuminate the
Recirculation Switch LED, but only while the but-
ton is pressed. Under this circumstance, the recir-
culation request will be denied and the fresh-air
door will remain in the fresh position. All door
positions are determined relative to the number of
commutator pulses required to provide full travel of
the door. On command, the A/C ± Heater Control
Module runs the actuator for the number of pulses
corresponding to the desired door position.
A/C Switch
The A/C Switch is a momentary contact switch.
Toggling the switch results in the A/C ± Heater
Control Module sending a change of state message
to the Powertrain Control Module (PCM ± gasoline)or Engine Control Module (ECM ± diesel) to provide
A/C compressor clutch activation or deactivation
respectively. The A/C ± Heater Control Module will
only provide this request if EVAP function is found
acceptable. The Power Switch must be on to make
the A/C switch active. The switch LED illuminates
when the switch is on. The A/C Switch setting is
remembered during power down.
Blower Switch
The rotary Blower Switch has five positions, Low,
M1, M2, M3, and High. The Power Switch must be
on to make the Blower Switch active. Toggling the
Power Switch results in the A/C ± Heater Control
Module sending a request to the FCM to provide
blower motor activation or deactivation respec-
tively.
Blend Switch ± Single Zone
The single rotary Blend Switch has multiple
detents to control the full range of temperature that
the system can produce in any mode. Rotating the
switch results in the A/C ± Heater Control Module
signaling the actuator to move the blend door. All
door positions are determined relative to the num-
ber of commutator pulses required to provide full
travel of the door. On command, the A/C ± Heater
Control Module runs the actuator for the number of
pulses corresponding to the desired door position.
Blend Switch ± Dual Zone
The dual sliding Blend Switches have multiple
detents to control the full range of temperature that
the system can produce an any mode. The upper
slide pot controls the driver-side blend door, while
the lower slide pot controls the passenger-side
blend door. Sliding the switch results in the A/C ±
Heater Control Module signaling the actuator to
move the blend door. All door positions are deter-
mined relative to the number of commutator pulses
required to provide full travel of the door. On
command, the A/C ± Heater Control Module runs
the actuator for the number of pulses corresponding
to the desired door position.
Mode Switch
The single rotary Mode Switch has 13 detents to
either direct airflow to the panel outlets, a mix of
floor and panel outlets, floor outlets, a mix of floor
and defrost outlets, or defrost outlets. Rotating the
switch results in the A/C ± Heater Control Module
signaling the actuator to move the mode door. All
door positions are determined relative to the num-
ber of commutator pulses required to provide full
travel of the door. On command, the A/C ± Heater
Control Module runs the actuator for the number of
pulses corresponding to the desired door position.
18
GENERAL INFORMATION