heater CHRYSLER CARAVAN 2003 Manual Online
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Page 1735 of 2177
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - WATER LEAKS
Water leaks can be caused by poor sealing,
improper body component alignment, body seam
porosity, missing plugs, or blocked drain holes. Cen-
trifugal and gravitational force can cause water to
drip from a location away from the actual leak point,
making leak detection difficult. All body sealing
points should be water tight in normal wet-driving
conditions. Water flowing downward from the front of
the vehicle should not enter the passenger or luggage
compartment. Moving sealing surfaces will not
always seal water tight under all conditions. At
times, side glass or door seals will allow water to
enter the passenger compartment during high pres-
sure washing or hard driving rain (severe) condi-
tions. Overcompensating on door or glass
adjustments to stop a water leak that occurs under
severe conditions can cause premature seal wear and
excessive closing or latching effort. After completing
a repair, water test vehicle to verify leak has stopped
before returning vehicle to use.
VISUAL INSPECTION BEFORE WATER LEAK TESTS
Verify that floor and body plugs are in place, body
drains are clear, and body components are properly
aligned and sealed. If component alignment or seal-
ing is necessary, refer to the appropriate section of
this group for proper procedures.
WATER LEAK TESTS
WARNING: DO NOT USE ELECTRIC SHOP LIGHTS
OR TOOLS IN WATER TEST AREA. PERSONAL
INJURY CAN RESULT.
When the conditions causing a water leak have
been determined, simulate the conditions as closely
as possible.
²If a leak occurs with the vehicle parked in a
steady light rain, flood the leak area with an open-
ended garden hose.
²If a leak occurs while driving at highway speeds
in a steady rain, test the leak area with a reasonable
velocity stream or fan spray of water. Direct the
spray in a direction comparable to actual conditions.
²If a leak occurs when the vehicle is parked on an
incline, hoist the end or side of the vehicle to simu-
late this condition. This method can be used when
the leak occurs when the vehicle accelerates, stops or
turns. If the leak occurs on acceleration, hoist the
front of the vehicle. If the leak occurs when braking,
hoist the back of the vehicle. If the leak occurs on left
turns, hoist the left side of the vehicle. If the leak
occurs on right turns, hoist the right side of the vehi-cle. For hoisting recommendations (Refer to LUBRI-
CATION & MAINTENANCE/HOISTING -
STANDARD PROCEDURE).
WATER LEAK DETECTION
To detect a water leak point-of-entry, do a water
test and watch for water tracks or droplets forming
on the inside of the vehicle. If necessary, remove inte-
rior trim covers or panels to gain visual access to the
leak area. If the hose cannot be positioned without
being held, have someone help do the water test.
Some water leaks must be tested for a considerable
length of time to become apparent. When a leak
appears, find the highest point of the water track or
drop. The highest point usually will show the point of
entry. After leak point has been found, repair the
leak and water test to verify that the leak has
stopped.
Locating the entry point of water that is leaking
into a cavity between panels can be difficult. The
trapped water may splash or run from the cavity,
often at a distance from the entry point. Most water
leaks of this type become apparent after accelerating,
stopping, turning, or when on an incline.
MIRROR INSPECTION METHOD
When a leak point area is visually obstructed, use
a suitable mirror to gain visual access. A mirror can
also be used to deflect light to a limited-access area
to assist in locating a leak point.
BRIGHT LIGHT LEAK TEST METHOD
Some water leaks in the luggage compartment can
be detected without water testing. Position the vehicle
in a brightly lit area. From inside the darkened lug-
gage compartment inspect around seals and body
seams. If necessary, have a helper direct a drop light
over the suspected leak areas around the luggage com-
partment. If light is visible through a normally sealed
location, water could enter through the opening.
PRESSURIZED LEAK TEST METHOD
When a water leak into the passenger compart-
ment cannot be detected by water testing, pressurize
the passenger compartment and soap test exterior of
the vehicle. To pressurize the passenger compart-
ment, close all doors and windows, start engine, and
set heater control to high blower in HEAT position. If
engine can not be started, connect a charger to the
battery to ensure adequate voltage to the blower.
With interior pressurized, apply dish detergent solu-
tion to suspected leak area on the exterior of the
vehicle. Apply detergent solution with spray device or
soft bristle brush. If soap bubbles occur at a body
seam, joint, seal or gasket, the leak entry point could
be at that location.
23 - 2 BODYRS
BODY (Continued)
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Page 1789 of 2177
INSTALLATION
NOTE: The crossbar assemblies are designed to be
installed in only one way. Check top and bottom
surfaces of the crossbar for the word FRONT and
directional arrows. The directional arrows must
point toward the front of the vehicle.
(1) Place crossbar in position on vehicle.
(2) Work from side to side sliding the crossbar
assembly back a little at a time to ensure it remains
perpendicular to the side rails.
(3) Position first crossbar assembly crossbar at the
second most rearward locator holes. Press the top of
the stanchion lever to lock it into position.
(4) Position the second crossbar assembly in the
second hole from the front. Lock into place.
(5) Place luggage rack riser into position.
(6) Install two fasteners into riser. Tighten fasten-
ers to 4 mm (35 in. lbs.) torque.
REAR QUARTER PANEL/
FENDER AIR EXHAUSTER
DESCRIPTION
Air exhausters, designed to conform to the body
structure, allow air entering at the front of the vehi-
cle to flow out the back. By reducing air pressure
within the vehicle, the exhausters also reduce blower
noise at any given air flow level compared to operat-
ing without them and help reduce door closing effort.
They are located in the lower rear comers of the
body.
REMOVAL
SHORT WHEELBASE
(1) Remove the rear fascia from the body. (Refer to
13 - FRAMES & BUMPERS/BUMPERS/REAR FAS-
CIA - REMOVAL).
(2) Using a trim stick or another suitable wide flat
bladed tool, carefully pry the air exhauster away
from the opening in the lower aperture panel until
the snap features release (Fig. 19).
(3) Remove the air exhauster from the hole in the
lower aperture panel.
LONG WHEELBASE
NOTE: Models with the optional rear heater and air
conditioner do not have an air exhauster on the
right side of the vehicle, but have a plastic plug
installed in the right lower aperture panel. This plug
is removed using the same procedure used toremove the air exhauster from the short wheelbase
model. Refer to SHORT WHEELBASE.
(1) Remove the quarter trim panel from the inside
of the left or right quarter inner panel (Refer to 23 -
BODY/INTERIOR/RIGHT QUARTER TRIM PANEL
- REMOVAL) or (Refer to 23 - BODY/INTERIOR/
LEFT QUARTER TRIM PANEL - REMOVAL).
(2) Using a trim stick or another suitable wide flat
bladed tool, carefully pry the air exhauster away
from the opening in the lower aperture panel until
the snap features release (Fig. 20).
(1) Remove the air exhauster from the hole in the
lower aperture panel.
Fig. 19 AIR EXHAUSTER - SWB
1 - LOWER APERTURE PANEL
2 - AIR EXHAUSTER
Fig. 20 AIR EXHAUSTER - LWB
1 - AIR EXHAUSTER
2 - PLUG
3 - LOWER APERTURE PANEL
23 - 56 EXTERIORRS
LUGGAGE RACK CROSSBAR (Continued)
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Page 1790 of 2177
INSTALLATION
SHORT WHEELBASE
(1) Position the air exhauster to the hole in the
lower aperture panel (Fig. 19).
(2) Using hand pressure, press the air exhauster
into the opening in the lower aperture panel until
the snap features are fully engaged.
(3) Reinstall the rear fascia onto the body. (Refer
to 13 - FRAMES & BUMPERS/BUMPERS/REAR
FASCIA - INSTALLATION).
LONG WHEELBASE
NOTE: Models with the optional rear heater and air
conditioner do not have an air exhauster on the
right side of the vehicle, but have a plastic plug
installed in the right lower aperture panel. This plug
is installed using the same procedure used to
install the air exhauster onto the short wheelbase
model. Refer to SHORT WHEELBASE.
(1) Position the air exhauster to the hole in the
lower aperture panel (Fig. 20).
(2) Using hand pressure, press the air exhauster
into the opening in the lower aperture panel until
the snap features are fully engaged.
(3) Reinstall the quarter trim panel onto the inside
of the left or right quarter inner panel. (Refer to 23 -
BODY/INTERIOR/RIGHT QUARTER TRIM PANEL
- INSTALLATION) or (Refer to 23 - BODY/INTERI-
OR/LEFT QUARTER TRIM PANEL - INSTALLA-
TION).
ROOF JOINT MOLDING
REMOVAL
The RAP molding is set with body side molding
tape. The temperature in the work area and the vehi-
cle should be at least 21É C (70É F) to avoid damag-
ing the RAP moldings.
(1) Warm the affected stick-on molding and body
metal to approximately 38É C (100É F) using a suit-
able heat lamp or heat gun.
(2) Pull stick-on molding from painted surface.
(3) Remove adhesive tape residue from painted
surface of vehicle. Use a 3M Scotch-BriteŸ Molding
Adhesive and Stripe Removal Discs, or equivalent, to
clean adhesive residue from painted surfaces. The
adhesive removal discs are available from automotive
paint suppliers. Refer to instructions supplied with
the discs for proper usage.
INSTALLATION
The RAP molding is set with body side molding
tape. The temperature in the work area and the vehi-
cle should be at least 21É C (70É F) to avoid damag-
ing the RAP moldings.
(1) If molding is to be reused;
(a) Remove tape residue from molding.
(b) Clean back of molding with MopartSuper
Kleen solvent, or equivalent.
(c) Wipe molding dry with lint free cloth.
(d) Apply new body side molding (two sided
adhesive) tape to back of molding.
(2) Clean body surface with MopartSuper Kleen
solvent, or equivalent. Wipe surface dry with lint free
cloth.
(3) Remove protective cover from tape on back of
molding.
(4) Apply molding to body from front of vehicle to
rear.
(5) Using a roller tool, roll molding onto body
panel with enough force to assure adhesion and not
bend roof panels.
SIDE VIEW MIRROR
REMOVAL
(1) Using a trim stick C-4755 or equivalent, lift up
the end of the instrument panel top pad enough to
gain access to the mirror electrical connector, if
equipped. (Refer to 23 - BODY/INSTRUMENT PAN-
EL/INSTRUMENT PANEL TOP COVER -
REMOVAL)
(2) Disconnect the electrical connector, if equipped.
(3) Using a trim stick or equivalent, remove the
trim cover (Fig. 21).
(4) Remove the bolts.
(5) Remove the mirror from the pillar.
INSTALLATION
(1) Route the mirror wire harness, if equipped,
through the a-pillar and place side view mirror in
position on vehicle (Fig. 21).
(2) Install the bolts and tighten to 10 N´m (85 in.
lbs.).
(3) Install the mirror trim cover.
(4) Connect the electrical connector, if equipped.
(5) Install the instrument panel top cover, if
equipped with the electric mirror. (Refer to 23 -
BODY/INSTRUMENT PANEL/INSTRUMENT
PANEL TOP COVER - INSTALLATION)
RSEXTERIOR23-57
REAR QUARTER PANEL/FENDER AIR EXHAUSTER (Continued)
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Page 1998 of 2177
HEATING & AIR CONDITIONING
TABLE OF CONTENTS
page page
HEATING & AIR CONDITIONING
DESCRIPTION
DESCRIPTION - SINGLE ZONE...........1
DESCRIPTION - DUAL ZONE.............1
DESCRIPTION - MANUAL THREE ZONE.....1
DESCRIPTION - AUTOMATIC
TEMPERATURE CONTROL...............2
OPERATION
OPERATION - DUAL ZONE...............3
OPERATION - MANUAL THREE ZONE......3
OPERATION - THREE ZONE ATC..........3
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - A/C COOL
DOWN TEST..........................4DIAGNOSIS AND TESTING - A/C
PERFORMANCE TEST..................5
DIAGNOSIS AND TESTING - HEATER
PERFORMANCE TEST..................6
SPECIFICATIONS - HEATER-A/C SYSTEM.....7
CONTROLS - FRONT......................8
CONTROLS - REAR......................29
DISTRIBUTION - FRONT...................39
DISTRIBUTION - REAR....................52
PLUMBING - FRONT.....................60
PLUMBING - REAR......................94
DIESEL SUPPLEMENTAL HEATER - DCHA -
EXPORT..............................106
HEATING & AIR
CONDITIONING
DESCRIPTION
DESCRIPTION - SINGLE ZONE
A single zone heating and air conditioning system
allows one temperature setting for the entire vehicle.
The full range of temperatures that the system can
produce are available by rotating the temperature
control located in control panel.
The control panel and integral computer is
mounted in the instrument panel.
DESCRIPTION - DUAL ZONE
A manual Dual Zone Heating and Air Conditioning
system allows completely independent side-to-side
tempeture control of the discharge air.
The control panel and integral computer is located
in the instrument panel.
The instrument panel mounted control and inte-
gral computer contains:
²a power button which allows the system to be
completely turned off. Contains an LED that illumi-
nates to show when the function is operational.
²rear window defogger on/off switch. Contains an
LED that illuminates to show when the function is
operational.
²slide controls for completely independent side-to-
side temperature control of the discharged air. The
full range of temperature that the system can pro-
duce in any mode is available on either side of thevehicle by independently positioning the slide con-
trols on the instrument panel.
²air recirculation on/off switch. The Recirculate
button contains an LED that illuminates to show
when the function is in operation.
²air conditioning on/off switch. The Snowflake
button contains an LED that illuminates to shown
when the function is in operation.
²rotary knob for fan speed selection.
²a rotary knob for mode control.
DESCRIPTION - MANUAL THREE ZONE
The fully adjustable Three-Zone front and rear
heating and air conditioning system allows interme-
diate seat passengers the ability to regulate air tem-
perature as well as fan speed. All controls are
identified by ISO graphic symbols.
FRONT CONTROL PANEL
The front control panel and integral computer is
mounted in the instrument panel.
The instrument panel mounted control and inte-
gral computer contains:
²a power button which allows the system to be
completely turned off.
²rear window defogger on/off switch.
²slide controls for completely independent side-to-
side temperature control of the discharge air. The full
range of temperature that the system can produce in
any mode is available on either side of the vehicle by
independently positioning the slide controls on the
instrument panel.
RSHEATING & AIR CONDITIONING24-1
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Page 1999 of 2177
²air recirculation button. The Recirculate button
contains an LED that illuminates to show when the
function is in operation.
²an air conditioning button that allows the com-
pressor to be turned on/off. The Snowflake button
contains an LED that illuminates to shown when the
function is in operation.
²rotary knobs for front and rear fan speed selec-
tion.
²a rotary knob for mode control.
REAR CONTROL PANEL
A rear control panel centrally mounted on the
headliner has a rotary adjustment for temperature
and fan speed control of the rear unit by intermedi-
ate seat passengers when the front control rear knob
is set to the rear position.
DESCRIPTION - AUTOMATIC TEMPERATURE
CONTROL
The Automatic Temperature Control (ATC) allows
occupants to select a comfort temperature, which is
the perceived temperature level not the actual pas-
senger compartment air temperature.
The Automatic Temperature Control system
includes a dust and odor air filter. The filter element
is the same size as the air conditioning evaporator to
ensure ample capacity. A door at the base of the
heater and air conditioning 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 Man-
ifold Absolute Pressure information from the 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
Fahrenheit.
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 infor-
mation, as identified by the Body Control Module
(BCM), to determine if all in-car temperatures should
be maintained.
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 VF tube 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
Failure, Rear Window Defogger Relay and A/C Select.
FRONT CONTROL PANEL
The front control panel and integral computer is
mounted in the instrument panel.
The instrument panel mounted control and inte-
gral computer contains:
²A power button which allows the system to be
completely turned off. The display is blank when the
system is off.
²Three rocker switches that select comfort tem-
peratures from 15É to 30É C (59É to 85É F), which are
shown in the vacuum-fluorescent digital control dis-
play. If the set temp is 59 and the down button is
pressed, the set temp value will become 55 but the
display will show LO. If the set temp is 85 and the
up button is pressed, the set temp value will become
90 but the display will show HIGH. Temperatures
can be displayed in either metric or Fahrenheit,
which is controlled from the overhead console.
²A rocker switch that selects a cool-down rate.
LO-AUTO or HI-AUTO are displayed when the sys-
tem is in automatic operation.
²A defroster button which turns on the defroster
independently during full automatic control. A
defroster symbol illuminates in the display when the
button is pressed.
24 - 2 HEATING & AIR CONDITIONINGRS
HEATING & AIR CONDITIONING (Continued)
ProCarManuals.com
Page 2000 of 2177
²Air recirculation button. A Recirculation symbol
appears in the display when the button is pressed, or
when the system exceeds 80 percent circulated air
under automatic control due to high air conditioning
demand.
²Rear window defogger on/off switch. A graphic
symbol shows when the defroster is on.
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.
²Rotary knob for front fan speed selection can
override the automatic controls. LEDs surrounding
the knob show the current setting.
²Rotary knob for control of the Rear system.
²A rotary knob for mode control can override the
automatic controls. LEDs surrounding the knob show
the current setting.
²Computer logic 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 provides variable air recircula-
tion 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 enables additional heat for diesel
equipped vehicles via a supplemental diesel heater.
REAR CONTROL PANEL
A rear control panel centrally mounted on the
headliner includes a vacuum-flourescent digital dis-
play, a rocker control for temperature and rotary con-
trols for adjustment of mode and fan speed control of
the rear unit by intermediate seat passengers.
OPERATION
OPERATION - DUAL ZONE
²The mode control knob enables continously vari-
able proportioning of air flow between modes but has
detents adjacent to each icon.
²The blower control provides five separate speeds.
²When the fan 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.
OPERATION - MANUAL THREE ZONE
FRONT CONTROL PANEL
²Primary control of the rear compartment unit is
on the instrument panel. This control allows the
driver to set the rear compartment fan speed, to turn
the rear unit off, or to give control to the intermedi-
ate seat occupants by switching to the REAR posi-
tion. When the rear unit is controlled from the
instrument panel, rear air temperature is based on
the driver-side temperature control position, and the
mode (floor or overhead air) is based on the front
control's mode position.
²The mode control knob enables continously vari-
able proportioning of air flow between modes but has
detents adjacent to each icon.
²The blower control provides five separate speeds
and Off. When the fan 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 exccept 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 indirectly the mode (floor or overhead air) of
the rear unit: a low temperature setting directs flow
to the overhead outlets and a high temperature set-
ting to the floor.
OPERATION - THREE ZONE ATC
Comfort temperature or perceived temperature is
affected by air flow, sun impinging on exposed skin,
etc. The air temperature may be higher or lower than
the comfort temperature. Two infrared sensors, in the
instrument panel center stack i measure the temper-
ature of the occupants to determine their comfort
level relative to the selected comfort temperature.
The HVAC computer in the control module adjusts
the air flow rate and temperature to maintain the
customer-perceived comfort temperature. The air
temperature in the passenger compartment at any
time may be slightly higher or lower than the com-
RSHEATING & AIR CONDITIONING24-3
HEATING & AIR CONDITIONING (Continued)
ProCarManuals.com
Page 2001 of 2177
fort temperature. 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. Infrared
Three-Zone Temperature Control provides side-to-
side and front-to-rear variation in comfort tempera-
ture settings. The Infrared Three-Zone Automatic
Temperature Control fan provides a continuously
variable air flow rate to meet occupant comfort
requirements.
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.
²DE-FROST± The de-frost function is active
when the rear window defogger function is active or
when the defog/defrost mode is selected.
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
Defogger and side view mirror (if equipped) circuitry.
The 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 function alone manual for
as long as the ignition is on. If only one is changed
manually, the other remains under automatic control.
Pressing the HI-AUTO/LO-AUTO rocker switch
restores full automatic control.
²REAR CONTROL± When the Rear System
control knob is moved to the OFF position, there will
be a delay of approximately 1 second before the sys-
tem actually turns off. This delay is to prevent an
undesired blower dropout if the knob is moved
through OFF to the other selections.
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, Defrost mode is
selected and the fan operates at a low speed to keep
the windshield fog free.
REAR CONTROL PANEL
Primary control of the rear compartment unit is in
the instrument panel center stack. The rear unit con-
trol knob there allows the driver to turn the rear
unit off, allow control by the intermediate seat occu-
pants by switching to the REAR position, or provide
fully automatic control based on the temperature set-
ting 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 front
control 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
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
24 - 4 HEATING & AIR CONDITIONINGRS
HEATING & AIR CONDITIONING (Continued)
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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 55É F or the test will fail immediately. The test
is activated by depressing the A/C and PWR buttons
simultaneously and holding them depressed for no
less than five seconds. The PWR 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 completed successfully. If the two
minutes expire without the expansion valve temper-
ature reaching 20É F less than the outside air tem-
perature, then the cool down test has been failed and
further A/C system diagnosis is required. If the test
is failed, the LEDs will continue to blink until the
vehicle has been driven for greater than (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 20É F less than the evaporator ini-
tial temperature, then the cool down test has been
failed and further A/C system diagnosis is required.
If the test is failed, the snowflake icon and the
DELAY text will continue to blink across ignition
cycles until the vehicle has been driven for greater
than (8 miles).
DIAGNOSIS AND TESTING - A/C
PERFORMANCE TEST
An air conditioning performance test is the best
way to determine whether the system is performing
up to standard. This test also provides valuable clues
as to the possible cause of trouble with the air con-
ditioning system. The ambient air temperature in the
location where the vehicle will be tested must be a
minimum of 21É C (70ÉF) for this test.
WARNING: REFER TO THE APPLICABLE WARN-
INGS AND CAUTIONS FOR THIS SYSTEM BEFOREPERFORMING THE FOLLOWING OPERATION.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - FRONT - WARNING - A/C PLUMBING)
and (Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - FRONT - CAUTION - A/C PLUMBING).
NOTE: When connecting the service equipment
coupling to the line fitting, verify that the valve of
the coupling is fully closed. This will reduce the
amount of effort required to make the connection.
(1) Connect a tachometer to monitor the engine
speed.
(2) Remove the caps from the refrigerant system
service ports and attach a manifold gauge set to
monitor the refrigerant system pressures.
(3) Set the heater-air conditioner controls so that
the compressor is engaged, the air within the vehicle
is being recirculated, the output air is directed
through the panel outlets, the temperature control is
in the full cool position, and the blower motor is oper-
ating at its highest speed.
(4) Start the engine and allow the engine to oper-
ate for about five minutes or until it reaches normal
operating temperature. Then hold the engine speed
at 1000 rpm with the compressor clutch engaged. If
the compressor clutch does not engage, proceed with
diagnosis of the compressor clutch coil. (Refer to 24 -
HEATING & AIR CONDITIONING/CONTROLS -
FRONT/COMPRESSOR CLUTCH COIL - DIAGNO-
SIS AND TESTING).
(5) Close all the vehicle windows and doors.
(6) Insert a thermometer in the left center panel
outlet and operate the engine for five minutes.
(7) With the compressor clutch engaged, record the
left center panel outlet discharge air temperature,
the discharge pressure (high side service port), and
the suction pressure (low side service port). The com-
pressor clutch may cycle, depending upon the ambi-
ent temperature and humidity. If the clutch cycles,
use the readings obtained before the clutch disen-
gaged.
(8) Compare the discharge air temperature read-
ing to the Performance Temperature and Pressure
chart. If the temperature reading is high, check the
refrigerant system for leaks and proper refrigerant
charge level. (Refer to 24 - HEATING & AIR CONDI-
TIONING/PLUMBING - FRONT/REFRIGERANT -
DIAGNOSIS AND TESTING - REFRIGERANT SYS-
TEM LEAKS) and (Refer to 24 - HEATING & AIR
CONDITIONING/PLUMBING - FRONT/REFRIGER-
ANT - DIAGNOSIS AND TESTING - REFRIGER-
ANT SYSTEM CHARGE LEVEL).
RSHEATING & AIR CONDITIONING24-5
HEATING & AIR CONDITIONING (Continued)
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Performance Temperature and Pressure
Ambient Temperature 21É C
(70É F)27É C
(80É F)32É C
(90É F)38É C
(100É F)43É C
(110É F)
Left Center Panel
Outlet Discharge Air
Temperature1to8ÉC
(34 to 46É F)3to9ÉC
(37 to 49É F)4 to 10ÉC
(39 to 50É F)6to11ÉC
(43 to 52É F)7 to 18É C
(45 to 65É F)
Discharge Pressure
(High Side Service
Port)1034 to 1724
kPa
(150 to 250
psi)1517 to 2275
kPa
(220 to 330
psi)1999 to 2620
kPa
(290 to 380
psi)2068 to 2965
kPa
(300 to 430
psi)2275 to 3421
kPa
(330 to 450 psi)
Suction Pressure (Low
Side Service Port)103 to 207 kPa
(15 to 30 psi)117 to 221 kPa
(17 to 32 psi)138 to 241 kPa
(20 to 35 psi)172 to 269 kPa
(25 to 39 psi)207 to 345 kPa
(30 to 50 psi)
DIAGNOSIS AND TESTING - HEATER
PERFORMANCE TEST
PRE-DIAGNOSTIC PREPARATIONS
WARNING: REFER TO THE APPLICABLE WARN-
INGS AND CAUTIONS FOR THIS SYSTEM BEFORE
PERFORMING THE FOLLOWING OPERATION.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING FRONT - WARNING - HEATER PLUMB-
ING).
Check the coolant level, drive belt tension, radiator
air flow, and cooling fan operation. Start the engine
and allow it to warm up to normal temperature.
MAXIMUM HEATER OUTPUT: TEST AND ACTION
Engine coolant is provided to the heater system by
two 16 mm (5/8 inch inside diameter) heater hoses.
With the engine idling at normal running tempera-
ture, set the heater-A/C controls as follows. Temper-
ature control to full Heat, Mode control to Floor,
Blower control to the highest speed setting. Using a
test thermometer, check the air temperature coming
from the center floor outlets and compare this read-
ing to the Temperature Reference table.
TEMPERATURE REFERENCE
AMBIENT
TEMPERATUREMINIMUM FLOOR
OUTLET
TEMPERATURE
CELSIUS FAHRENHEIT CELSIUS FAHRENHEIT
15.5É 60É 62.2É 144É
21.1É 70É 63.8É 147É
26.6É 80É 65.5É 150É
32.2É 90É 67.2É 153ÉIf the floor outlet air temperature is insufficient,
check that the cooling system is operating to specifi-
cations. (Refer to 7 - COOLING/ENGINE - DIAGNO-
SIS AND TESTING). Both heater hoses should be
HOT to the touch (the coolant return hose should be
slightly cooler than the supply hose). If the coolant
return hose is much cooler than the supply hose,
locate and repair the engine coolant flow obstruction
in heater system.
POSSIBLE LOCATIONS OR CAUSE OF OBSTRUCTED
COOLANT FLOW
²Pinched or kinked heater hoses.
²Improper heater hose routing.
²Plugged heater hoses or supply and return ports
at cooling system connections.
²Plugged heater core.
²Air locked heater core.
²Restrictor in backwards.
If coolant flow is verified and the heater floor out-
let temperature is insufficient, a mechanical problem
may exist.
POSSIBLE LOCATION OR CAUSE OF INSUFFICIENT HEAT
²Obstructed cowl air intake.
²Obstructed heater system outlets.
²Blend-air door not functioning properly.
TEMPERATURE CONTROL
If heater floor outlet temperature cannot be
adjusted with the heater-A/C control temperature
control lever, one of the following could require ser-
vice:
²Blend-air door binding.
²Faulty blend-air door motor.
²Improper engine coolant temperature.
²Faulty heater-A/C control.
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SPECIFICATIONS - HEATER-A/C SYSTEM
ITEM DESCRIPTION NOTES
Vehicle RS - Caravan, Town & Country, Voyager
System R134a with expansion valve(s)
Compressor Nippondenso - 10S20 ND-8 PAG Oil
Freeze±up Control Evaporator temperature sensor Expansion valve mounted - input
to heater-A/C control module
Low PSI Control Pressure transducer Liquid line mounted - input to
Powertrain Control Module (PCM)
- PCM opens compressor clutch
relay < 29.4 psi
High PSI Control Pressure transducer Liquid line mounted - input to
PCM - PCM opens compressor
clutch relay > 450 psi
Pressure relief valve Compressor mounted - opens >
495 psi
Control Head Single zone, dual zone, and three zone
Manual Temperature Control (MTC) - or
Automatic Temperature Control (ATC), (Two
or Three Zone)PCI data bus messaging - ATC
uses two infrared temperature
sensors
Mode Door Electric actuator Control head driven
Blend Air Door Electric actuator
Fresh/Recirc Door Electric actuator
Blower Motor Control head switch Resistor and relay with MTC,
power module and relay with ATC
Cooling Fans Pulse width modulated variable speed PCM control through solid state
fan relay
Clutch
Clutch Control PCM PCM control through compressor
clutch relay
Clutch Coil Draw 2.2 amps @ 12V 0.5amps@ 70É F
Compressor Clutch Air Gap 0.0209- 0.0359
Diagnostics DRBIIITscan tool
RSHEATING & AIR CONDITIONING24-7
HEATING & AIR CONDITIONING (Continued)
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