
Condition Possible Causes Correction
The low side pressure is too
low, and the high side
pressure is too high.1. Restricted refrigerant flow
through the refrigerant lines.1. See Liquid Line, Suction Line and Discharge
Line in this group. Inspect the refrigerant lines for
kinks, tight bends or improper routing. Correct
the routing or replace the refrigerant line, if
required.
2. Restricted refrigerant flow
through the A/C expansion
valve.2. See A/C Expansion Valve in this group.
Replace the valve, if required.
3. Restricted refrigerant flow
through the A/C condenser.3. See A/C Condenser in this group. Replace the
restricted condenser, if required.
DIAGNOSIS AND TESTING - HEATER
PERFORMANCE TEST
WARNING: REVIEW SAFETY PRECAUTIONS AND
WARNINGS IN THIS GROUP BEFORE PERFORMING
THIS PROCEDURE (Refer to 24 - HEATING & AIR
CONDITIONING/PLUMBING - WARNING).
Check the coolant level, drive belt tension, radiator
air flow and fan operation. Start engine and allow to
warm up to normal operating temperature.
WARNING: DO NOT REMOVE RADIATOR CAP
WHEN ENGINE IS HOT, PERSONAL INJURY CAN
RESULT.
If vehicle has been run recently, wait 15 minutes
before removing the radiator cap. Place a rag overthe cap and turn it to the first safety stop. Allow
pressure to escape through the overflow tube. When
the system pressure stabilizes, remove the cap com-
pletely.
MAXIMUM HEATER OUTPUT: TEST AND ACTION
Engine coolant is provided to the heater system by
two heater hoses. With the engine idling at normal
operating temperature, set the temperature control
to maximum heat, the mode control to the floor posi-
tion, and the blower in the highest speed position.
Using a test thermometer, check the temperature of
the air being discharged from the floor outlets. Com-
pare the test thermometer reading to the Tempera-
ture Reference chart.
TEMPERATURE REFERENCE
Ambient Temperature Minimum 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 153É
If 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.OBSTRUCTED COOLANT FLOW Possible locations or causes
of obstructed coolant flow are as follows:
²Pinched or kinked heater hoses.
²Improper heater hose routing.
²Plugged heater hoses or supply and return ports
at the cooling system connections.
²Plugged heater core.
If proper coolant flow through the cooling system is
verified, and heater outlet air temperature is insuffi-
cient, a mechanical problem may exist.
24 - 10 HEATING & AIR CONDITIONINGRS
HEATING & AIR CONDITIONING (Continued)

MECHANICAL PROBLEMS
Possible causes of insufficient heat due to mechan-
ical problems are as follows:
²Obstructed cowl air intake.
²Obstructed heater system outlets.
²Blend door not functioning properly.
TEMPERATURE CONTROL
If the heater outlet air temperature cannot be
adjusted with the temperature control knob on the
A/C-heater control panel, the following could require
service:
²Blend door binding.²Faulty blend door actuator.
²Faulty A/C-heater control.
²Faulty related wiring harness or connectors.
²Improper engine coolant temperature.
SPECIFICATIONS
A/C SYSTEM
The R-134a refrigerant system charge capacity for
this vehicle can be found on the underhood Specifica-
tion Label.
SYSTEM SPECIFICATIONS
Item Description Notes
A/C Compressor Denso - 10S20 (2.5L/3.3L/3.8L engines)
Denso - 10S17 (2.4L engine)ND-8 PAG Oil
Freeze±up Control Evaporator temperature sensor Expansion valve mounted (ATC),
HVAC housing mounted (MTC)-
input to A/C-heater control
module
Low PSI Control A/C pressure transducer Liquid line mounted - input to
Powertrain Control Module (PCM)
- PCM opens compressor clutch
relay above 200 kPa (29 psi)
High PSI Control A/C pressure transducer Liquid line mounted - input to
PCM - PCM opens compressor
clutch relay below 3100 kPa (450
psi)
High Pressure relief valve Compressor mounted - opens
above 3445-4135 kPa (500-600
psi), closes below 2756 kPa (400
psi)
Compressor Clutch Coil Draw 2.2 amps @ 12V 0.5V @ 21É C (70É F)
Compressor Clutch Air Gap 0.35 - 0.60 mm (0.014 - 0.025 in.)
TORQUE SPECIFICATIONS
Description N´m Ft. Lbs. In. Lbs.
A/C Compressor Shaft
Bolt17.5 ± 155
A/C Compressor Mounting
Bolts (2.4L/2.5L)28 21 ±
A/C Compressor Mounting
Bolts (3.3L/3.8L)54 40 ±
A/C Compressor Mounting
Bracket Bolts (2.4L)54 40 ±
A/C Condenser Mounting
Bracket Screws5±45
RSHEATING & AIR CONDITIONING24-11
HEATING & AIR CONDITIONING (Continued)

Description N´m Ft. Lbs. In. Lbs.
A/C Expansion Valve
Screws11 ± 9 7
A/C-Heater Control
Screws2±17
Blend Door Actuator
Screws2±17
Blower Motor Screws 2 ± 17
Blower Motor Power
Module Screws (ATC)2±17
Blower Motor Resistor
Block Screws (MTC)2±17
Center Bezel Outlet
Screws2±17
Distribution Housing
Screws2±17
Discharge Line to
Compressor Nut23 17 ±
Discharge Line to
Condenser Nut23 17 ±
Front Fascia Screws 6 ± 53
Front Fascia Grille Insert
Screws2±17
Heater Core Mounting
Plate Screws2±17
Heater Core Sealing Plate
Screws3±26
Hood Latch Screws 14 ± 123
HVAC Housing Bracket
Bolt3±26
HVAC Housing Mounting
Nuts7±62
HVAC Housing Mounting
Bolts4±35
Liquid Line to Condenser
Nut23 17 ±
Liquid Line to Receiver/
drier Bolt11 ± 9 7
Lower Air inlet Housing
Screws2±17
Mode Door Actuator
Screws2±17
Quarter Trim Panel
Attaching Bracket Screws2±17
Rear Blower Motor
Screws2±17
Rear Blower Motor Power
Module Screws (ATC)2±17
24 - 12 HEATING & AIR CONDITIONINGRS
HEATING & AIR CONDITIONING (Continued)

Description N´m Ft. Lbs. In. Lbs.
Rear Blower Motor
Resistor Block Screws
(MTC)2±17
Rear Capture Plate Screw 2 ± 17
Rear Evaporator Line Seal
Plate to Rear Expansion
Valve Nut23 17 ±
Rear Expansion Valve
Bracket Nut23 17 ±
Rear Expansion Valve
Bracket Screws2±17
Rear Expansion Valve to
Rear Evaporator Screws11 ± 9 7
Rear Floor Heat Duct
Screws2±17
Rear HVAC Housing
Screws2±17
Rear HVAC Housing
Mounting Screws11 ± 9 7
Rear HVAC Housing Stud
Nuts9±80
Rear Mode Door Actuator
Screws2±17
Receiver/drier Bracket
Nuts10 ± 89
Recirculation Door
Actuator Screws2±17
Refrigerant Lines to
Expansion Valve Nut23 17 ±
Suction Line to
Compressor Nut23 17 ±
Cabin Heater Air Intake
Pipe Screws7±62
Cabin Heater M6 Bolts 7 ± 62
Cabin Heater M8 Bolts 23 17 ±
Cabin Heater Seat Hex
Nut60 44 ±
Underbody Liquid Line
Fitting23 17 ±
Underbody Refrigerant
Line Sealing Plate Screw23 17 ±
Underbody Suction Line
Fitting23 17 ±
Upper Air Inlet Housing
Screws2±17
RSHEATING & AIR CONDITIONING24-13
HEATING & AIR CONDITIONING (Continued)

CONTROLS - FRONT
TABLE OF CONTENTS
page page
A/C COMPRESSOR CLUTCH/COIL
DESCRIPTION.........................15
OPERATION...........................15
DIAGNOSIS AND TESTING - A/C
COMPRESSOR CLUTCH COIL...........15
REMOVAL.............................16
INSPECTION..........................17
INSTALLATION.........................17
A/C COMPRESSOR CLUTCH RELAY
DESCRIPTION.........................19
OPERATION...........................19
REMOVAL.............................20
INSTALLATION.........................20
A/C HEATER CONTROL
DESCRIPTION.........................20
STANDARD PROCEDURE - A/C-HEATER
CONTROL CALIBRATION...............20
REMOVAL.............................21
INSTALLATION.........................21
A/C PRESSURE TRANSDUCER
DESCRIPTION.........................21
OPERATION...........................21
DIAGNOSIS AND TESTING - A/C PRESSURE
TRANSDUCER.......................22
REMOVAL.............................22
INSTALLATION.........................22
BLEND DOOR ACTUATOR
DESCRIPTION.........................23
OPERATION...........................23
REMOVAL.............................23
INSTALLATION.........................23
BLOWER MOTOR RELAY
DESCRIPTION.........................24
OPERATION...........................24
REMOVAL.............................25
INSTALLATION.........................25
BLOWER MOTOR RESISTOR BLOCK
DESCRIPTION.........................26OPERATION...........................26
DIAGNOSIS AND TESTING - BLOWER
MOTOR RESISTOR BLOCK..............26
REMOVAL.............................26
INSTALLATION.........................27
EVAPORATOR TEMPERATURE SENSOR
DESCRIPTION.........................27
OPERATION...........................28
REMOVAL
REMOVAL - AUTOMATIC TEMPERATURE
CONTROL (ATC)......................28
REMOVAL - MANUAL TEMPERATURE
CONTROL (MTC)......................29
INSTALLATION
INSTALLATION - AUTOMATIC
TEMPERATURE CONTROL (ATC).........29
INSTALLATION - MANUAL TEMPERATURE
CONTROL (MTC)......................29
INFRARED TEMPERATURE SENSOR
DESCRIPTION.........................29
OPERATION...........................29
MODE DOOR ACTUATOR
DESCRIPTION.........................30
OPERATION...........................30
REMOVAL.............................30
INSTALLATION.........................31
POWER MODULE - BLOWER MOTOR
DESCRIPTION.........................31
OPERATION...........................31
REMOVAL.............................31
INSTALLATION.........................32
RECIRCULATION DOOR ACTUATOR
DESCRIPTION.........................32
OPERATION...........................32
REMOVAL.............................33
INSTALLATION.........................33
24 - 14 CONTROLS - FRONTRS

A/C COMPRESSOR CLUTCH/
COIL
DESCRIPTION
The A/C compressor clutch assembly consists of a
stationary electromagnetic A/C clutch field coil with a
zener diode, a pulley bearing and pulley assembly,
and a clutch plate (Fig. 1). A/C clutch field coil and
the pulley bearing and pulley assembly are each
retained on the nose of the compressor front housing
with snap rings. The clutch plate is keyed or splined
to the compressor shaft, and secured with a nut or
bolt (depending on application). These components
provide the means to engage and disengage the com-
pressor from the engine serpentine accessory drive
belt.
The A/C compressor clutch and coil are available
for separate service replacement. The clutch coil
zener diode is integral to the clutch coil pigtail wire
and connector and, if faulty or damaged, the clutch
electromagnetic coil must be replaced.
OPERATION
The compressor clutch components provide the
means to engage and disengage the compressor from
the engine serpentine accessory drive belt. When the
clutch coil is energized, it magnetically draws the
clutch plate into contact with the clutch pulley and
drives the compressor shaft. When the coil is not
energized, the pulley freewheels on the clutch hub
bearing, which is part of the pulley.
A zener diode is connected in parallel with the
clutch electromagnetic coil. This diode controls the
dissipation of voltage induced into the coil windingsby the collapsing of the electromagnetic fields that
occurs when the compressor clutch is disengaged.
The zener diode dissipates this induced voltage by
regulating a current path to ground. This arrange-
ment serves to protect other circuits and components
from potentially damaging voltage spikes in the vehi-
cle electrical system that might occur if the voltage
induced in the clutch coil windings could not be dis-
sipated.
The compressor clutch engagement is controlled by
several components: the heater-A/C controls in the
passenger compartment, the A/C pressure transducer
on the liquid line, the evaporator temperature sensor
on the expansion valve for automatic temperature
control (ATC) system or on the HVAC housing for
manual temperature control (MTC) system, the Pow-
ertrain Control Module (PCM) in the engine compart-
ment, and the compressor clutch relay in the
Integrated Power Module (IPM). The PCM may delay
compressor clutch engagement for up to thirty sec-
onds (Refer to 8 - ELECTRICAL/ELECTRONIC
CONTROL MODULES/POWERTRAIN CONTROL
MODULE - DESCRIPTION - PCM OPERATION).
DIAGNOSIS AND TESTING - A/C COMPRESSOR
CLUTCH COIL
The air conditioning compressor clutch coil electri-
cal circuit is controlled by the powertrain control
module (PCM) through the A/C compressor clutch
relay, which is located in the integrated power mod-
ule (IPM) in the engine compartment. Begin testing
of a suspected compressor clutch coil problem by per-
forming the preliminary checks.
PRELIMINARY CHECKS
(1) If the compressor clutch will not engage, verify
the refrigerant charge level (Refer to 24 - HEATING
& AIR CONDITIONING/PLUMBING - FRONT/RE-
FRIGERANT - DIAGNOSIS AND TESTING -
REFRIGERANT CHARGE LEVEL). If the refriger-
ant charge level is OK, go to Step 2. If the refriger-
ant charge level is not OK, adjust the refrigerant
charge as required.
(2) If the A/C compressor clutch still will not
engage, disconnect the wire harness connector for the
A/C pressure transducer and check for battery cur-
rent at the connector with the engine running and
the A/C-heater control set to the A/C mode. If OK, go
to TESTS. If not OK, refer to Body Diagnostic Proce-
dures to perform further diagnosis.
TESTS
(1) Verify the battery state of charge (Refer to 8 -
ELECTRICAL/BATTERY SYSTEM/BATTERY -
DIAGNOSIS AND TESTING).
Fig. 1 Compressor Clutch - Typical
1 - CLUTCH PLATE
2 - SHAFT KEY (SOME MODELS)
3 - PULLEY AND BEARING
4 - CLUTCH COIL
5 - CLUTCH SHIMS
6 - SNAP RING
7 - SNAP RING
RSCONTROLS - FRONT24-15

(2) Connect an ammeter (0 to 10 ampere scale
selected) in series with the clutch coil feed terminal.
Connect a voltmeter (0 to 20 volt scale selected) to
measure voltage across the battery and the clutch
coil.
(3) With the heater-A/C control in the A/C mode
and the blower at low speed, start the engine and
allow it to run at a normal idle speed.
(4) The compressor clutch should engage immedi-
ately, and the clutch coil voltage should be within
two volts of the battery voltage. If the coil voltage is
not within two volts of battery voltage, test the
clutch coil feed circuit for excessive voltage drop. If
the compressor clutch does not engage, refer to Body
Diagnostic Procedures to perform further diagnosis.
(5) Refer to the A/C Clutch Coil Current Draw
chart for the acceptable A/C clutch coil current draw
specifications. Specifications apply for a work area
temperature of 21É C (70É F). If voltage is more than
12.5 volts, add electrical loads by turning on electri-
cal accessories until voltage reads below 12.5 volts.
(a) If the compressor clutch coil current reading
is zero, the coil is open and must be replaced.
(b) If the compressor clutch coil current reading
is four amperes or more, the coil is shorted and
must be replaced.
A/C CLUTCH COIL CURRENT DRAW
Compressor Current Draw
Nippondenso - 10S20
(2.5L/3.3L/3.8L engines)
Nippondenso - 10S17
(2.4L engine)2.2 amps @ 11.5 - 12.5
volts
REMOVAL
NOTE: The compressor clutch can be serviced in
the vehicle. The refrigerant system can remain fully-
charged during compressor clutch, pulley, or coil
replacement.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the serpentine drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
2.4L - REMOVAL) or (Refer to 7 - COOLING/ACCES-
SORY DRIVE/DRIVE BELTS - 3.3/3.8L -
REMOVAL).
(3) Raise and support the vehicle.
(4) Disconnect the engine wire harness connector
for the compressor clutch coil from the clutch coil pig-
tail wire connector on the top of the compressor.
(5) On models with the 3.3L and 3.8L engines, dis-
engage the retainer on the engine wire harness com-
pressor clutch coil take out from the bracket on the
top of the compressor.(6) On models with the 2.4L and 2.5L engines,
remove all of the compressor mounting bolts except
the upper left (rear of the compressor), which should
only be loosened. Allow the front (pulley end) of the
compressor to tilt downward far enough to access the
clutch for removal, then tighten the loosened upper
left compressor mounting bolt.
(7) On models with the 3.3L and 3.8L engines,
remove the two bolts and two nuts that secure the
compressor to the engine. Disengage the mounting
ear at the front of the compressor from the stud on
the engine, allow the front (pulley end) of the com-
pressor to tilt downward far enough to access the
clutch for removal, then reinstall and tighten the
upper left compressor mounting bolt.
(8) Remove the compressor shaft bolt (Fig. 2). A
band-type oil filter wrench or a strap wrench may be
used to secure the clutch during bolt removal.
(9) Tap the clutch plate lightly with a plastic mal-
let to release it from the splines on the compressor
shaft. Remove the clutch plate and shim(s) from the
compressor shaft (Fig. 3).
NOTE: Use care not to lose any of the shim(s).
CAUTION: Do not pry between the clutch plate unit
and the pulley to remove the clutch plate from the
compressor shaft as this may damage the clutch
plate.
Fig. 2 Compressor Shaft Bolt and Clutch Plate
1 - COMPRESSOR SHAFT BOLT
2 - COMPRESSOR CLUTCH PLATE
24 - 16 CONTROLS - FRONTRS
A/C COMPRESSOR CLUTCH/COIL (Continued)

COOLING/ACCESSORY DRIVE/DRIVE BELTS -
3.3L/3.8L - INSTALLATION).
(15) Lower the vehicle.
(16) Reconnect the battery negative cable.
CLUTCH BREAK-IN
After a new compressor clutch has been installed,
cycle the compressor clutch approximately twenty
times (five seconds on, then five seconds off). During
this procedure, set the A/C-heater control to the A/C
Recirculation Mode, the blower motor switch in the
highest speed position, and the engine speed at 1500
to 2000 rpm. This procedure (burnishing) will seat
the opposing friction surfaces and provide a higher
compressor clutch torque capability.
A/C COMPRESSOR CLUTCH
RELAY
DESCRIPTION
The compressor clutch relay (Fig. 7) is a Interna-
tional Standards Organization (ISO) micro-relay.
Relays conforming to the ISO specifications have
common physical dimensions, current capacities, ter-
minal patterns, and terminal functions. The ISO
micro-relay terminal functions are the same as a con-
ventional ISO relay. However, the ISO micro-relay
terminal pattern (or footprint) is different, the cur-
rent capacity is lower, and the physical dimensions
are smaller than those of the conventional ISO relay.
The A/C compressor clutch relay is located in the
Integrated Power Module (IPM) in the engine com-
partment. See the fuse and relay layout map molded
into the inner surface of the IPM cover for A/C com-
pressor clutch relay identification and location.The black, molded plastic case is the most visible
component of the A/C compressor clutch relay. Five
male spade-type terminals extend from the bottom of
the base to connect the relay to the vehicle electrical
system, and the ISO designation for each terminal is
molded into the base adjacent to each terminal. The
ISO terminal designations are as follows:
²30 (Common Feed)- This terminal is con-
nected to the movable contact point of the relay.
²85 (Coil Ground)- This terminal is connected
to the ground feed side of the relay control coil.
²86 (Coil Battery)- This terminal is connected
to the battery feed side of the relay control coil.
²87 (Normally Open)- This terminal is con-
nected to the normally open fixed contact point of the
relay.
²87A (Normally Closed)- This terminal is con-
nected to the normally closed fixed contact point of
the relay.
OPERATION
The A/C compressor clutch relay is an electrome-
chanical switch that uses a low current input from
the powertrain control module (PCM) to control the
high current output to the compressor clutch electro-
magnetic coil. The movable common feed contact
point is held against the fixed normally closed con-
tact point by spring pressure. When the relay coil is
energized, an electromagnetic field is produced by the
coil windings. This electromagnetic field draws the
movable relay contact point away from the fixed nor-
mally closed contact point, and holds it against the
fixed normally open contact point. When the relay
coil is de-energized, spring pressure returns the mov-
able contact point back against the fixed normally
closed contact point. The resistor or diode is con-
nected in parallel with the relay coil in the relay, and
helps to dissipate voltage spikes and electromagnetic
interference that can be generated as the electromag-
netic field of the relay coil collapses.
The compressor clutch relay terminals are con-
nected to the vehicle electrical system through a
receptacle in the integrated power module (IPM). The
inputs and outputs of the A/C compressor clutch
relay include:
²The common feed terminal (30) receives a bat-
tery current input from a fuse in the IPM through a
fused B(+) circuit at all times.
²The coil ground terminal (85) receives a ground
input from the PCM through the compressor clutch
relay control circuit only when the PCM electroni-
cally pulls the control circuit to ground.
²The coil battery terminal (86) receives a battery
current input from the PCM through a fused ignition
switch output (run-start) circuit only when the igni-
tion switch is in the On or Start positions.
Fig. 7 A/C Compressor Clutch Relay
RSCONTROLS - FRONT24-19
A/C COMPRESSOR CLUTCH/COIL (Continued)