heating CHRYSLER VOYAGER 2001 Service Manual

The downstream heated oxygen sensor threads into
the outlet pipe at the rear of the catalytic convertor
(Fig. 19).
OPERATION
Separate controlled ground circuits are run
through the PCM for the upstream O2 sensors.
As vehicles accumulate mileage, the catalytic con-
vertor deteriorates. The deterioration results in a
less efficient catalyst. To monitor catalytic convertor
deterioration, the fuel injection system uses two
heated oxygen sensors. One sensor upstream of the
catalytic convertor, one downstream of the convertor.
The PCM compares the reading from the sensors to
calculate the catalytic convertor oxygen storage
capacity and converter efficiency. Also, the PCM uses
the upstream heated oxygen sensor input when
adjusting injector pulse width.
When the catalytic converter efficiency drops below
emission standards, the PCM stores a diagnostic
trouble code and illuminates the malfunction indica-
tor lamp (MIL).
The O2S produce voltages from 0 to 1 volt, depend-
ing upon the oxygen content of the exhaust gas in
the exhaust manifold. When a large amount of oxy-
gen is present (caused by a lean air/fuel mixture), the
sensors produces a low voltage. When there is a
lesser amount present (rich air/fuel mixture) it pro-
duces a higher voltage. By monitoring the oxygen
content and converting it to electrical voltage, the
sensors act as a rich-lean switch.The oxygen sensors are equipped with a heating
element that keeps the sensors at proper operating
temperature during all operating modes. Maintaining
correct sensor temperature at all times allows the
system to enter into closed loop operation sooner.
Also, it allows the system to remain in closed loop
operation during periods of extended idle.
In Closed Loop operation the PCM monitors the
O2S input (along with other inputs) and adjusts the
injector pulse width accordingly. During Open Loop
operation the PCM ignores the O2 sensor input. The
PCM adjusts injector pulse width based on prepro-
grammed (fixed) values and inputs from other sen-
sors.
The Automatic Shutdown (ASD) relay supplies bat-
tery voltage to both the upstream and downstream
heated oxygen sensors. The oxygen sensors are
equipped with a heating element. The heating ele-
ments reduce the time required for the sensors to
reach operating temperature.
UPSTREAM OXYGEN SENSOR
The input from the upstream heated oxygen sensor
tells the PCM the oxygen content of the exhaust gas.
Based on this input, the PCM fine tunes the air-fuel
ratio by adjusting injector pulse width.
The sensor input switches from 0 to 1 volt, depend-
ing upon the oxygen content of the exhaust gas in
the exhaust manifold. When a large amount of oxy-
gen is present (caused by a lean air-fuel mixture), the
sensor produces voltage as low as 0.1 volt. When
there is a lesser amount of oxygen present (rich air-
fuel mixture) the sensor produces a voltage as high
as 1.0 volt. By monitoring the oxygen content and
converting it to electrical voltage, the sensor acts as
a rich-lean switch.
The heating element in the sensor provides heat to
the sensor ceramic element. Heating the sensor
allows the system to enter into closed loop operation
sooner. Also, it allows the system to remain in closed
loop operation during periods of extended idle.
In Closed Loop, the PCM adjusts injector pulse
width based on the upstream heated oxygen sensor
input along with other inputs. In Open Loop, the
PCM adjusts injector pulse width based on prepro-
grammed (fixed) values and inputs from other sen-
sors.
DOWNSTREAM OXYGEN SENSOR
The downstream heated oxygen sensor input is
used to detect catalytic convertor deterioration. As
the convertor deteriorates, the input from the down-
stream sensor begins to match the upstream sensor
input except for a slight time delay. By comparing
the downstream heated oxygen sensor input to the
Fig. 19 O2 SENSOR DOWNSTREAM 1/2 - 2.4/3.3/
3.8L
1 - 1/2 02S
2 - 1/1 02S
RSFUEL INJECTION14-31
O2 SENSOR (Continued)

FLUID
STANDARD PROCEDURE - FLUID LEVEL AND
CONDITION CHECK
NOTE: Only transmission fluid of the type labeled
Mopar ATF+4 (Automatic Transmission Fluid±Type
9602) should be used in this transaxle.
FLUID LEVEL CHECK
The transmission sump has a fluid level indicator
(dipstick) to check oil similar to most automatic
transmissions. It is located on the left side of the
engine. Be sure to wipe all dirt from dipstick handle
before removing.
The torque converter fills in both the P Park and N
Neutral positions. Place the selector lever in P Park
to be sure that the fluid level check is accurate.The
engine should be running at idle speed for at
least one minute, with the vehicle on level
ground.At normal operating temperature (approxi-
mately 82 C. or 180 F.), the fluid level is correct if it
is in the HOT region (cross-hatched area) on the oil
level indicator (Fig. 214). The fluid level should be
within the WARM range of the dipstick at 70É F fluid
temperature.
FLUID LEVEL CHECK USING DRB
NOTE: Engine and Transaxle should be at normal
operating temperature before performing this proce-
dure.
(1) Start engine and apply parking brake.
(2) Hook up DRB scan tool and select transmis-
sion.(3) Select sensors.
(4) Read the transmission temperature value.
(5) Compare the fluid temperature value with the
fluid temperature chart (Fig. 215).
(6) Adjust transmission fluid level shown on the
indicator according to the chart.
(7) Check transmission for leaks.
Low fluid level can cause a variety of conditions
because it allows the pump to take in air along with
the fluid. As in any hydraulic system, air bubbles
make the fluid spongy, therefore, pressures will be
low and build up slowly.
Improper filling can also raise the fluid level too
high. When the transaxle has too much fluid, the
gears churn up foam and cause the same conditions
which occur with a low fluid level.
In either case, air bubbles can cause overheating
and/or fluid oxidation, and varnishing. This can
interfere with normal valve, clutch, and accumulator
operation. Foaming can also result in fluid escaping
from the transaxle vent where it may be mistaken
for a leak.
FLUID CONDITION
Along with fluid level, it is important to check the
condition of the fluid. When the fluid smells burned,
and is contaminated with metal or friction material
particles, a complete transaxle recondition is proba-
bly required. Be sure to examine the fluid on the dip-
stick closely. If there is any doubt about its condition,
drain out a sample for a double check.
Moparž ATF+4 (Automatic Transmission Fluid-
Type 9602) when new is red in color. The ATF is dyed
red so it can be identified from other fluids used in
the vehicle such as engine oil or antifreeze. The red
color is not permanent and is not an indicator of fluid
condition. As the vehicle is driven, the ATF will begin
to look darker in color and may eventually become
brown. This is normal. A dark brown/black fluid
accompanied with a burnt odor and/or deterioration
in shift quality may indicate fluid deterioration or
transmission component failure.
After the fluid has been checked, seat the dipstick
fully to seal out water and dirt.
STANDARD PROCEDURE - FLUID AND FILTER
SERVICE
NOTE: Refer to the maintenance schedules in
LUBRICATION and MAINTENANCE, or the vehicle
owner's manual, for the recommended maintenance
(fluid/filter change) intervals for this transaxle.
Fig. 214 Transaxle Fluid Level Indicator
1 - TRANSAXLE DIPSTICK
21 - 246 AUTOMATIC - 41TERS

CLEANING - TIRES
Before delivery of a vehicle, remove the protective
coating on the tires with white sidewalls or raised
white letters. To remove the protective coating, apply
warm water and let it soak for a few minutes. After-
wards, scrub the coating away with a soft bristle
brush. Steam cleaning may also be used to remove
the coating.
CAUTION: DO NOT use gasoline, mineral oil, oil-
based solvent or a wire brush for cleaning.
WHEELS
DESCRIPTION - WHEEL
Original equipment wheels are designed for proper
operation at all loads up to the specified maximum
vehicle capacity.
All models use either steel or aluminum drop-cen-
ter wheels. Every wheel has raised sections between
the rim flanges and rim drop well called safety
humps (Fig. 23). Initial inflation of the tires forces
the bead over these raised sections. In case of air
loss, the safety humps hold the tire in position on the
wheel until the vehicle can be brought to a safe stop.
Cast aluminum wheels require special balance
weights to fit on the flange of the rim (Fig. 24).
When wheel alignment is necessary on a vehicle
with cast aluminum wheels, special wheel clamps are
required to avoid damage to the wheel's finish.The wheel studs and nuts are designed for specific
wheel applications and must be replaced with equiv-
alent parts.
All aluminum wheels have wheel mounting (lug)
nuts with an enlarged nose. This enlarged nose is
necessary to ensure proper retention of the wheels.
DIAGNOSIS AND TESTING - WHEEL
INSPECTION
Inspect wheels for:
²Excessive runout
²Dents, cracks or irregular bends
²Damaged wheel stud (lug) holes
²Air Leaks
NOTE: Do not attempt to repair a wheel by hammer-
ing, heating or welding.
If a wheel is damaged, an original equipment
replacement wheel should be used. When obtaining
replacement wheels, they should be equivalent in
load carrying capacity. The diameter, width, offset,
pilot hole and bolt circle of the wheel should be the
same as the original wheel.
WARNING: FAILURE TO USE EQUIVALENT
REPLACEMENT WHEELS MAY ADVERSELY
AFFECT THE SAFETY AND HANDLING OF THE
VEHICLE.
WARNING: REPLACEMENT WITH USED WHEELS IS
NOT RECOMMENDED. THE SERVICE HISTORY OF
THE WHEEL MAY HAVE INCLUDED SEVERE TREAT-
MENT OR VERY HIGH MILEAGE. THE RIM COULD
FAIL WITHOUT WARNING.
Fig. 23 Safety Rim
1 - TIRE
2 - WELL
3 - SAFETY HUMPS
4 - FLANGE
Fig. 24 Styled Aluminum Wheel Weight
1 - TIRE
2 - WHEEL
3 - STYLED WHEEL WEIGHT
RSTIRES/WHEELS22-13
TIRES (Continued)

moldings. After each length is applied, drive the vehi-
cle. If noise goes away after a piece of tape is applied,
remove tape, locate, and repair defect.
POSSIBLE CAUSE OF WIND NOISE
²Moldings standing away from body surface can
catch wind and whistle.
²Gaps in sealed areas behind overhanging body
flanges can cause wind-rushing sounds.
²Misaligned movable components.
²Missing or improperly installed plugs in pillars.
²Weld burn through holes.
STANDARD PROCEDURE - PLASTIC BODY
PANEL REPAIR
Resin Transfer Molded (RTM) body panels are rein-
forced with a continuous fiberglass mesh. Epoxy
resin is injected into a gel-coated and fiberglass lined
mold to form a body panel. Sheet molded compound
(SMC) body panels are constructed with fiberglass
strands usually 1 inch or shorter, epoxy resin formed
into sheet stock and pressed in mold flowing material
to form a sheet molded compound (SMC) body panel.
RTM and SMC body panels can be repaired with
epoxy adhesive after market products. Refer to
instructions provided by the manufacturer of prod-
ucts being used to repair RTM or SMC.
DaimlerChrysler Corporation recommends that a
trained automotive body technician perform body
panel repair procedures (Fig. 1).
SAFETY PRECAUTION AND WARNINGS
WARNING: EYE PROTECTION SHOULD BE USED
WHEN SERVICING RTM AND SMC COMPONENTS.
PERSONAL INJURE CAN RESULT.USE AN OSHA
APPROVED BREATHING DEVICE WHEN MIXING
EPOXY, GRINDING RTM AND SMC, AND SPRAYING
PAINT OR SOLVENTS IN A CONFINED AREA. PER-
SONAL INJURY CAN RESULT.AVOID PROLONGEDSKIN CONTACT WITH EPOXY RESIN, PETROLEUM,
OR ALCOHOL BASED SOLVENTS. PERSONAL
INJURY CAN RESULT.DO NOT VENTURE UNDER A
HOISTED VEHICLE THAT IS NOT PROPERLY SUP-
PORTED ON SAFETY STANDS. PERSONAL INJURY
CAN RESULT.
²When holes must be drilled or cut in body pan-
els, verify locations of internal body components and
electrical wiring. Damage to vehicle can result.
²Do not use abrasive chemicals or compounds on
undamaged painted surfaces around repair areas.
Damage to finish can result.
If it is required to section a large panel for an SMC
or RTM repair, it will be necessary to reinforce the
panel with epoxy structural adhesive (rigid repair
adhesive) (Fig. 2). To bond two plastic panels
together, a reinforcement must overlap both panels.
The panels must be ªV'dº at a 20 degree angle. The
area to be reinforced should be washed, then sanded.
Be sure to wipe off any excess soap and water when
finished. Lightly sand or abrade the plastic with an
abrasive pad or sandpaper. Blow off any dust with
compressed air or wipe with a clean dry rag.
When bonding SMC or RTM panels, use a two-part
epoxy adhesive. Properly mix parts A and B, and
apply it to the panels being repaired. Be sure that
enough adhesive has been applied to allow squeeze
out and to fill the full bond line. Once the pieces
have been brought together, do not move them until
the adhesive is cured. The assembly can be held
together with clamps, rivets, etc. A faster cure can be
obtained by heating with a heat lamp or heat gun.
After the parts have been bonded and have had
time to cure, rough sand the seam and apply the
final adhesive filler to the area being repaired.
Fig. 1 Panel Repair
Fig. 2 Panel Sectioning
1 - EXISTING PANEL
2 - NEW PANEL
3 - PANEL ADHESIVE
4 - BONDING STRIP
23 - 4 BODYRS
BODY (Continued)

HEATING & AIR CONDITIONING
TABLE OF CONTENTS
page page
HEATING & AIR CONDITIONING
DESCRIPTION............................1
OPERATION.............................3
DIAGNOSIS AND TESTING..................4
A/C COOL DOWN TEST...................4
A/C PERFORMANCE TEST................5
HEATER PERFORMANCE TEST............6SPECIFICATIONS.........................7
CONTROLS - FRONT......................8
CONTROLS - REAR......................30
DISTRIBUTION - FRONT...................41
DISTRIBUTION - REAR....................54
PLUMBING - FRONT......................62
PLUMBING - REAR.......................96
HEATING & AIR
CONDITIONING
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 Dual Zone Heating and Air Conditioning sys-
tem includes a dust and odor air filter. The filter ele-
ment is the same size as the air conditioning
evaporator to ensure ample capacity. A door at the
base of the heating and air conditioning housing
below the glove box provides easy access to the filter
element.
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 the
vehicle 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.
The Three Zone Heating and Air Conditioning sys-
tem includes a dust and odor air filter. The filter ele-
ment is the same size as the air conditioning
evaporator to ensure ample capacity. A door at the
base of the heating and air conditioning housing
below the glove box provides easy access to the filter
element.
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.
²air recirculation button. The Recirculate button
contains an LED that illuminates to show when the
function is in operation.
RSHEATING & AIR CONDITIONING24-1

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 - THREE ZONE Automatic
Temperature Control
The Three-Zone Automatic Temperature Control
(ATC) allows occupants to select a comfort tempera-
ture, which is the perceived temperature level not
the actual passenger compartment air temperature.
The Three Zone Automatic Temperature Control
system includes a dust and odor air filter. The filter
element is the same size as the air conditioning evap-
orator 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 cooldown 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.
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.
24 - 2 HEATING & AIR CONDITIONINGRS
HEATING & AIR CONDITIONING (Continued)

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 of, 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.
²A graphic symbol of the windshield that illumi-
nates when the windshield wiper deicer is active.
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 - 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 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 temperautres 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 temperautres 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. Three infrared sensors, two
in the instrument panel center stack, and one in the
overhead-mounted rear control panel, independently
measure the temperature of the driver, front passen-
ger, and rear compartment 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 tempera-
ture. The air temperature in the passenger compart-
ment at any time may be slightly higher or lower
than the comfort temperature. For instance, on
sunny summer days the air flow will probably be
cooler than the comfort temperature; on cold or
RSHEATING & AIR CONDITIONING24-3
HEATING & AIR CONDITIONING (Continued)

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 temperature 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 front 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 OFF 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 engineis 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 - 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.
24 - 4 HEATING & AIR CONDITIONINGRS
HEATING & AIR CONDITIONING (Continued)

MANUAL TEMPERATURE CONTROL
The front blower speed 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 after two minutes, then the cool
down test has been completed successfully. If the two
minutes expire without the evaporator temperature
reaching 20É F less than the outside air temperature,
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 across ignition cycles
until the vehicle has been driven for greater than (3
miles).
AUTOMATIC TEMPERATURE CONTROL
The outside air temperature shown in the ATC dis-
play must not be lower than 53É F or the test will not
begin. 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 after 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 (3 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 BEFORE
PERFORMING 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)

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.
24 - 6 HEATING & AIR CONDITIONINGRS
HEATING & AIR CONDITIONING (Continued)