²a rotary adjustment knob for temperature.
²a rotary adjustment for fan speed control.
AUTOMATIC TEMPERATURE CONTROL
Two different automatic temperature control (ATC)
heating-A/C systems are available for this model
depending on the market.
The Dual-Zone ATC system allows the driver and
front occupants to each select individual comfort tem-
peratures.
The Three-Zone ATC system allows both the driver
and front occupants and the rear intermediate occu-
pants to select individual comfort temperatures.
NOTE: Individual comfort temperatures are the per-
ceived temperature level at the individual seating
areas, NOT the actual passenger compartment air
temperature.
The ATC system includes a particulate air filter.
The filter element is the same size as the A/C evap-
orator to ensure ample capacity. A door at the base of
the HVAC housing below the glove box provides easy
access to the filter element.
The ATC computer utilizes integrated circuitry and
information carried on the programmable communi-
cations interface (PCI) data bus network to monitor
many sensors and switch inputs throughout the vehi-
cle. In response to those inputs, the internal circuitry
and programming of the ATC computer allow it to
control electronic functions and features of the ATC
system. The inputs to the ATC computer are:
²Vehicle Speed/Engine RPM± The ATC com-
puter monitors engine rpm, vehicle speed and mani-
fold absolute pressure information from the
powertrain control module (PCM).
²Coolant Temperature± ATC computer moni-
tors coolant temperature received from the PCM and
converts it to degrees Fahrenheit.
²Ambient Temperature± ATC computer moni-
tors ambient temperature from the compass mini trip
computer (CMTC) and converts it to degrees Fahren-
heit.
²Engine Miscellaneous Sensor Status±ATC
computer monitors A/C disable information from the
PCM.
²Refrigerant Pressure± ATC computer moni-
tors barometric pressure, intake air temperature,
high side pressure and methanol content as broad-
cast by the PCM.
²Door Ajar Status± The ATC computer moni-
tors driver front door, passenger front door, left rear
door, right rear door and liftgate ajar information, as
identified by the body control module (BCM), to
determine if all in-car temperatures should be main-
tained.²Dimming± The ATC computer monitors dim-
ming status from the BCM to determine the required
level of brightness and will dim accordingly.
²Vehicle Odometer± The ATC computer moni-
tors the vehicle odometer information from the BCM
to prevent flashing the vacuum-flourescent (VF) dig-
ital display icons if the manual motor calibration or
manual cool down tests have failed. Flashing of the
display icons will cease when the vehicle odometer is
greater than 3 miles.
²English/Metric± The ATC computer monitors
the English/Metric information broadcast by the
CMTC. The set temp displays for both the front and
rear control heads will be set accordingly.
²Vehicle Identification Number± The ATC
computer monitors the last eight characters of the
VIN broadcast by the PCM and compares it to the
information stored in EEPROM. If it is different, the
new number will be stored over the old one and a
motor calibration shall be initiated.
²A/C System Information± The ATC computer
will send a message for evaporator temperature too
low, fan blower relay status, evaporator sensor fail-
ure, rear window defogger relay and A/C select.
FRONT CONTROL PANEL
The front A/C-heater control and integral computer
is mounted in the instrument panel and contains:
²a power button which allows the system to be
completely turned off. The display is blank when the
system is off.
²a rocker switch that selects a cool-down rate.
LO-AUTO or HI-AUTO are displayed when the sys-
tem is in automatic operation.
²three rocker switches that select comfort temper-
atures from 15É to 30É C (59É to 85É F), which are
shown in the VF digital display. If the set temp is 15É
C (59É F) and the down button is pressed, the set
temp value will become 13É C (55É F) but the display
will show LO. If the set temp is 29É C (85É F) and the
up button is pressed, the set temp value will become
32É C (90É F) but the display will show HIGH. Tem-
peratures can be displayed in either metric or Fahr-
enheit, which is controlled from the overhead console.
²an air conditioning button that allows the com-
pressor to be turned off. A Snowflake symbol is illu-
minated when air conditioning is on, whether under
manual or automatic control.
²an air recirculation button. A Recirculation sym-
bol appears in the display when the button is
pressed, or when the system exceeds 80 percent recir-
culated air under automatic control due to high air
conditioning demand.
²a rear window defogger on/off switch. A graphic
symbol shows when the defroster is on.
RSHEATING & AIR CONDITIONING24-3
HEATING & AIR CONDITIONING (Continued)
NOTE: Prior to a vehicle being removed from ser-
vice or stored for more than two weeks, the com-
pressor should be operated to ensure adequate
refrigerant oil distribution throughout the system
components. Turn on the air conditioner for a min-
imum of five minutes with outside air and the high-
est blower speed selected.
BELT NOISE
If the compressor drive belt slips at initial start-up,
it does not necessarily mean the compressor has
failed. The following procedure can be used to iden-
tify a compressor drive belt noise problem.
A. Start the vehicle and run at idle.
B. Turn the air conditioner On and listen for belt
squeal.
C. If belt squeal is heard, turn the air conditioner
Off immediately.
If the belt squeal stops when the air conditioner is
turned Off, perform the following repair procedures.
(1) Using an appropriate sized oil filter wrench or
a strap wrench, grasp the outer diameter of the com-
pressor clutch hub. While facing the compressor,
rotate the hub clockwise, then counterclockwise. If
the hub rotates, proceed to the next step. If the hub
will not rotate, the compressor is internally damaged,
and must be replaced.
(2) Turn the hub clockwise five complete revolu-
tions and remove the tool.
(3) Start the vehicle and run at idle.
(4) Turn the air conditioner On. Observe the com-
pressor and the system for normal operation, noting
cooling performance and noise levels. Operate for five
minutes before turning the air conditioner Off. If
acceptable cooling performance is observed during
compressor operation, the compressor does not need
to be replaced.
(5) Inspect the drive belt for wear, damage, and
proper tension. (Refer to 7 - COOLING/ACCESSORY
DRIVE/DRIVE BELTS - DIAGNOSIS AND TEST-
ING).
REMOVAL
A/C COMPRESSOR
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).(1) Recover the refrigerant from the refrigerant
system (Refer to 24 - HEATING & AIR CONDITION-
ING/PLUMBING - FRONT/REFRIGERANT - STAN-
DARD PROCEDURE - REFRIGERANT SYSTEM
RECOVERY).
(2) Disconnect and isolate the negative battery
cable.
(3) Remove the nuts that secure the A/C suction
line and the A/C discharge line to the A/C compres-
sor.
(4) Disconnect the A/C suction line and the A/C
discharge line from the A/C compressor.
(5) Remove the O-ring seal and gasket from the
suction and discharge line fittings and discard.
(6) Install plugs in, or tape over the opened suc-
tion and discharge fittings and the compressor ports.
(7) Raise and support the vehicle.
(8) Remove the accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(9) Disconnect the wire harness connector from the
compressor clutch coil wire connector located on the
top of the A/C compressor (Fig. 4) or (Fig. 5).
(10) On models with the 2.4L, 2.5L and 2.8L
engine, remove the four bolts that secure the A/C
compressor to the mounting bracket on the engine
(2.4L), or the cylinder block (2.5L/2.8L).
Fig. 4 A/C Compressor - 2.4L Shown, 2.5L/2.8L
Typical
1 - CLUTCH COIL WIRE CONNECTOR
2 - DISCHARGE PORT
3 - A/C COMPRESSOR
4 - SUCTION PORT
5 - BOLT (4)
6 - A/C COMPRESSOR MOUNTING BRACKET
RSPLUMBING - FRONT24-73
A/C COMPRESSOR (Continued)
(7) Lubricate a new rubber O-ring seal with clean
refrigerant oil and install it on the liquid line fitting.
(8) Reconnect the A/C liquid line to the receiver/
drier.
(9) Install the bolt that secures the A/C liquid line
to the receiver/drier. Tighten the bolt to 11 N´m (97
in. lbs.).
(10) If equipped, reinstall the A/C ground strap
eyelet terminal connector onto the weld stud on the
top of the right front strut tower (if equipped).
(11) If equipped, install the nut that secures the
A/C ground strap to the weld stud. Tighten the nut
to 12 N´m (106 in. lbs.)
(12) Install the A/C pressure transducer (Refer to
24 - HEATING & AIR CONDITIONING/CONTROLS
- FRONT/A/C PRESSURE TRANSDUCER - INSTAL-
LATION).
(13) Connect the drain tube to the wiper module
drain on the right side of the engine compartment.
(14) Install the air cleaner housing into the right
side of the engine compartment.
(15) On RHD models, install the liquid line into
the retaining bracket located at the top of the dash
panel.
(16) If the vehicle is equipped with the optional
rear heating-A/C system, go to Step 17. If the vehicle
does not have the optional rear heating-A/C system,
go to Step 23.
(17) Raise and support the vehicle.
(18) Remove the tape or plugs from the A/C liquid
line extension fitting and the underbody liquid line
fitting.
(19) Lubricate a new rubber O-ring seal with clean
refrigerant oil and install it on the underbody liquid
line fitting.
(20) Connect the A/C liquid line extension fitting
to the underbody liquid line fitting. Tighten the fit-
tings to 23 N´m (17 ft. lbs.).
(21) Install a new tie strap just forward of the con-
nections between the underbody plumbing and the
engine compartment plumbing for the rear heating-
A/C system.
(22) Lower the vehicle.
(23) Reconnect the negative battery cable.
(24) Evacuate the refrigerant system (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
FRONT/REFRIGERANT - STANDARD PROCE-
DURE - REFRIGERANT SYSTEM EVACUATE).
(25) Charge the refrigerant system (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
FRONT/REFRIGERANT - STANDARD PROCE-
DURE - REFRIGERANT SYSTEM CHARGE).RECEIVER / DRIER
DESCRIPTION
The receiver/drier is mounted in a bracket secured
to the right front strut tower in the engine compart-
ment. The receiver/drier is connected between the
front and rear sections of the liquid line between the
condenser outlet and the evaporator inlet. The receiv-
er/drier cannot be repaired. If the receiver/drier is
faulty or damaged, or if the refrigerant system has
been contaminated or left open to the atmosphere for
an indeterminable period or if the A/C compressor
has failed, it must be replaced.
OPERATION
The receiver/drier performs a filtering action to
prevent foreign material in the refrigerant from con-
taminating the expansion valve. Desiccant inside the
receiver/drier canister absorbs any moisture which
may have entered and become trapped within the
refrigerant system. In addition, during periods of
high demand air conditioner operation, the receiver/
drier acts as a reservoir to store surplus refrigerant.
Refrigerant enters the receiver/drier as a high-pres-
sure, low temperature liquid.
REMOVAL
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).
(1) Recover the refrigerant from the refrigerant
system (Refer to 24 - HEATING & AIR CONDITION-
ING/PLUMBING - FRONT/REFRIGERANT - STAN-
DARD PROCEDURE - REFRIGERANT
RECOVERY).
(2) Remove the air cleaner housing from the right
side of the engine compartment.
(3) Remove the bolt that secures the liquid line
front section fitting to the top of the receiver/drier
(Fig. 30).
(4) Disconnect the liquid line fitting from the
receiver/drier inlet port.
(5) Remove the O-ring seal from the liquid line fit-
ting and discard.
(6) Install plugs in, or tape over the opened liquid
line fitting and the receiver/drier inlet port.
24 - 92 PLUMBING - FRONTRS
LIQUID LINE (Continued)