2003 JEEP GRAND CHEROKEE battery housing

INSTALLATION
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Prior to installing the instrument panel into
the vehicle, loosen the three nuts that secure the
instrument panel intermediate bracket and the accel-
erator pedal assembly to the studs on the dash panel
(Fig. 8).
(2) With the aid of an assistant, load the instru-
ment panel assembly through the driver side front
door of the vehicle and hang it on the studs on the
dash panel near the windshield fence line (Fig. 1).
(3) Be certain that the molded plastic hook forma-
tions on the instrument panel structural duct are
inserted into and seated in the guide holes at each
cowl side inner panel.
(4) Loosely install the two screws that secure each
end of the instrument panel to the cowl side inner
panels.
(5) Install and tighten the two screws that secure
the passenger side instrument panel structural duct
to the heater and air conditioner housing (Fig. 13).
Tighten the screws to 11.8 N´m (105 in. lbs.).
(6) Install and tighten the one screw that secures
the instrument panel steering column support
bracket to the driver side end of the heater and air
conditioner housing (Fig. 7). Tighten the screw to
11.8 N´m (105 in. lbs.).
(7) Tighten the two screws that secure each end of
the instrument panel to the cowl side inner panels
(Fig. 10) and (Fig. 14). Tighten the screws to 11.8
N´m (105 in. lbs.).
(8) Install and tighten the one screw that secures
the instrument panel steering column support
bracket to the intermediate bracket on the driver
side dash panel (Fig. 8). Tighten the screw to 11.3
N´m (100 in. lbs.).
(9) Tighten the three nuts that secure the instru-
ment panel intermediate bracket and the accelerator
pedal assembly to the studs on the dash panel.
Tighten the nuts to 11.3 N´m (100 in. lbs.).(10) Install and tighten the four nuts that secure
the instrument panel to the studs on the dash panel
near the windshield fence line. Tighten the nuts to
11.8 N´m (105 in. lbs.).
(11) Install and tighten the nut that secures the
instrument panel steering column support bracket to
the stud on the driver side cowl plenum panel (Fig.
9). Tighten the nut to 28.2 N´m (250 in. lbs.).
(12) Reinstall the instrument panel to center floor
tunnel bracket onto the instrument panel and the
floor panel transmission tunnel. (Refer to 23 - BODY/
INSTRUMENT PANEL/IP CENTER FLOOR TUN-
NEL BRACKET - INSTALLATION).
(13) Reconnect the two instrument panel wire har-
ness connectors to the two heater and air conditioner
housing connectors located near the blower motor on
the passenger side end of the housing (Fig. 12).
(14) Reconnect the two halves of the radio antenna
coaxial cable connector near the right cowl side inner
panel under the end of the instrument panel.
(15) Reconnect the instrument panel wire harness
connector to the lower cavity of the inline connector
on the passenger side cowl side inner panel and
tighten the connector screw (Fig. 11). Tighten the
screw to 4 N´m (36 in. lbs.).
(16) Reinstall the lower right center bezel onto the
instrument panel. (Refer to 23 - BODY/INSTRU-
MENT PANEL/IP LOWER RIGHT CENTER BEZEL
- INSTALLATION).
(17) Reinstall the end cap onto the instrument
panel. (Refer to 23 - BODY/INSTRUMENT PANEL/
INSTRUMENT PANEL END CAP - INSTALLA-
TION).
(18) If the vehicle is equipped with the manual
heating and air conditioning system, reconnect the
vacuum harness connector located near the driver
side of the floor panel transmission tunnel behind
the driver side floor duct.
(19) Position the driver side floor duct to the
heater and air conditioner housing near the driver
side of the floor panel transmission tunnel (Fig. 7).
(20) Install and tighten the one screw that secures
the driver side floor duct to the heater and air con-
ditioner housing near the driver side of the floor
panel transmission tunnel. Tighten the screw to 2.2
N´m (20 in. lbs.).
(21) Route the instrument panel wire harness to
the floor panel transmission tunnel and engage the
retainers that secure the harness to the mounting
brackets on the tunnel (Fig. 6).
(22) Install the instrument panel wire harness
ground eyelets to the studs on the floor panel trans-
mission tunnel in front of and behind the airbag con-
trol module and secure the eyelets with nuts. Tighten
the nuts to 7.3 N´m (65 in. lbs.).
WJINSTRUMENT PANEL SYSTEM 23 - 43
INSTRUMENT PANEL SYSTEM (Continued)

(23) Reconnect the instrument panel wire harness
connectors to the following floor panel transmission
tunnel components:
²the Airbag Control Module (ACM) connector
receptacle
²the park brake switch terminal
²the transmission shifter connector receptacle.
(24) Reconnect the left and right body wire har-
ness connectors, the Ignition Off Draw (IOD) wire
harness connector and the fused B(+) wire harness
connector to the connector receptacles of the Junction
Block (JB) and tighten the connector screws (Fig. 5).
Tighten the screws to 4 N´m (36 in. lbs.).
(25) Engage the lower steering column shaft with
the steering shaft coupler and position the steering
column to the mounting studs on the instrument
panel steering column support bracket (Fig. 4).
(26) Install and tighten the four nuts that secure
the steering column to the studs on the instrument
panel steering column support bracket. Tighten the
nuts to 11.8 N´m (105 in. lbs.).
(27) Install and tighten the bolt that secures the
coupler to the lower steering column shaft. Tighten
the bolt to 49 N´m (36 ft. lbs.).
(28) Turn the ignition switch to the On position,
then install the shifter interlock cable connector into
the ignition lock housing receptacle.
(29) Reconnect the instrument panel wire harness
connectors to the following steering column compo-
nents (Fig. 3):
²the two lower clockspring connector receptacles
²the left multi-function switch connector recepta-
cle
²the right multi-function switch connector recep-
tacle
²the two ignition switch connector receptacles
²the shifter interlock solenoid connector recepta-
cle
²if the vehicle is so equipped, the Sentry Key
Immobilizer Module (SKIM) connector receptacle.
(30) Position the lower tilting steering column
shroud to the steering column multi-function switchmounting housing, then install and tighten the screw
that secures the shroud to the housing (Fig. 2).
Tighten the screw to 1.9 N´m (17 in. lbs.).
(31) Position the upper tilting steering column
shroud over the steering column. Align the upper and
lower shrouds with each other and snap the two
halves together.
(32) Reinstall the steering column bracket onto the
instrument panel steering column support bracket.
(Refer to 23 - BODY/INSTRUMENT PANEL/IP
STEERING COLUMN BRACKET - INSTALLA-
TION).
(33) Reinstall the steering column opening cover
onto the instrument panel. (Refer to 23 - BODY/IN-
STRUMENT PANEL/STEERING COLUMN OPEN-
ING COVER - INSTALLATION).
(34) Reinstall the cluster bezel onto the instru-
ment panel. (Refer to 23 - BODY/INSTRUMENT
PANEL/CLUSTER BEZEL - INSTALLATION).
(35) Reinstall the fuse cover onto the Junction
Block (JB). (Refer to 8 - ELECTRICAL/POWER DIS-
TRIBUTION/FUSE COVER - INSTALLATION).
(36) Reinstall the console onto the floor panel
transmission tunnel. (Refer to 23 - BODY/INTERI-
OR/FLOOR CONSOLE - INSTALLATION).
(37) Reinstall the trim panels onto the right and
left inner cowl sides. (Refer to 23 - BODY/INTERI-
OR/COWL TRIM - INSTALLATION).
(38) Reinstall the scuff plates onto the right and
left front door sills. (Refer to 23 - BODY/INTERIOR/
DOOR SILL SCUFF PLATE - INSTALLATION).
(39) Reinstall the top cover onto the instrument
panel. (Refer to 23 - BODY/INSTRUMENT PANEL/
INSTRUMENT PANEL TOP COVER - INSTALLA-
TION).
(40) Reinstall the trim onto the right and left
A-pillars. (Refer to 23 - BODY/INTERIOR/A-PILLAR
TRIM - INSTALLATION).
(41) Reconnect the battery negative cable.
23 - 44 INSTRUMENT PANEL SYSTEMWJ
INSTRUMENT PANEL SYSTEM (Continued)

POWER OUTLET DOOR
REMOVAL
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the center lower bezel from the instru-
ment panel. (Refer to 23 - BODY/INSTRUMENT
PANEL/IP CENTER BEZEL - LOWER - REMOVAL).
(3) With the power outlet door in the open posi-
tion, carefully spread the power outlet door hinge
arms far enough to disengage the pivot pins from the
pivots on the back side of the center lower bezel (Fig.
38).
NOTE: The power outlet door is more easily ser-
viced while in the open position. The illustration
shows the door in the closed position for improved
visibility of the assist spring orientation and anchor
point details.
(4) Disengage the stepped ends of the assist spring
from the anchor holes in the inboard power outlet
door hinge arm and in the side of the ash receiver
housing.
(5) Remove the power outlet door from the instru-
ment panel center lower bezel.
INSTALLATION
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Position the power outlet door to the instru-
ment panel center lower bezel.
(2) Engage the stepped ends of the assist spring
with the anchor holes in the inboard power outlet
door hinge arm and in the side of the ash receiver
housing (Fig. 38).
(3) With the power outlet door in the open posi-
tion, carefully spread the power outlet door hinge
arms far enough to engage the pivot pins with the
pivots on the back side of the lower center bezel.
(4) Reinstall the center lower bezel into the instru-
ment panel. (Refer to 23 - BODY/INSTRUMENT
PANEL/IP CENTER BEZEL - LOWER - INSTALLA-
TION).
(5) Reconnect the battery negative cable.
Fig. 38 Instrument Panel Power Outlet Door
Remove/Install
1 - CENTER LOWER BEZEL
2 - ASH RECEIVER FLAME SHIELD
3 - ASH RECEIVER HOUSING
4 - PIVOT PINS
5 - ASSIST SPRING
6 - POWER OUTLET DOOR HINGE ARMS
WJINSTRUMENT PANEL SYSTEM 23 - 67

SUNROOF
TABLE OF CONTENTS
page page
SUNROOF
DESCRIPTION.........................96
DIAGNOSIS AND TESTING - SUNROOF......96
DRAIN TUBE
REMOVAL............................100
INSTALLATION........................100
CONTROL MODULE
REMOVAL............................101
INSTALLATION........................101
DRIVE MOTOR
REMOVAL............................101
INSTALLATION........................101
WIND DEFLECTOR
REMOVAL............................102INSTALLATION........................102
GLASS PANEL
REMOVAL............................102
INSTALLATION........................103
ADJUSTMENTS
ADJUSTMENTS - FIT.................103
ADJUSTMENT - TIMING...............103
SUNSHADE
REMOVAL............................103
INSTALLATION........................103
HOUSING ASSEMBLY
REMOVAL............................104
INSTALLATION........................104
SUNROOF
DESCRIPTION
WARNING: Keep fingers and other body parts out
of sunroof opening at all times.
The sunroof features a power sliding glass panel
and a sunshade which can be manually positioned
anywhere along its travel, rearward of glass panel
front edge.
The sunroof is electrically operated from a switch
located on the mini overhead console. To operate the
sunroof the ignition switch must be in the On/Run
position. The sunroof has both manual and Express
Open modes of operation when opening. To open the
sunroof in the Express Open mode, the switch is
pressed rearward for less than1 second.This causes
the sunroof glass to automatically retract and stop at
a position slightly forward of full open that reduces
low speed wind buffeting. The sunroof can also be
opened manually by pressing and holding the switch
rearward. Once the switch is held reward for more
than1 second,the glass will retract in the manual
mode. Releasing the switch at any time during travel
will cause the sunroof to stop at the current position.
To close the sunroof from an open position, the
switch must be pushed forward and held until the
sunroof glass comes to a complete stop. Releasing the
switch at any time in this mode will cause the sun-
roof to stop at the current position.
To vent the sunroof from the closed position, the
switch is pushed forward and held. Releasing theswitch at any time during travel will cause the sun-
roof to stop at the current vent position. To reach the
fully vented position, continue to hold the switch for-
ward until vent motion stops. To close the sunroof
from the vent position, push and hold the switch
rearward until the glass comes to a complete stop.
DIAGNOSIS AND TESTING - SUNROOF
CAUTION: The sunroof motor is only to be powered
through the vehicle battery and vehicle wire har-
ness. Applying power to the sunroof motor leads
will cause failure of the sunroof control unit.
Before beginning sunroof diagnostics verify that all
other power accessories are in proper operating con-
dition. Refer to Sunroof Diagnostic Chart for possible
causes. If not, a common electrical problem may
exist. Refer to Group 8W, Wiring Diagrams, of this
publication for circuit, splice and component descrip-
tions. Check the condition of the circuit protection
(20 amp high current fuse (battery feed) located in
the Power Distribution Center (PDC). Check the
cover of the PDC for location of the fuse. Check for
correct operation of the sunroof delay relay. Inspect
all wiring connector pins for proper engagement and
continuity. Check for battery voltage at battery and
ignition pins of the power sunroof express module
wiring connector. Refer to Group 8W, Wiring Dia-
grams, for circuit information. The controller will not
operate at less than 10 volts. Check the ground at
the sunroof express module.
Before beginning diagnosis for wind noise or water
leaks, verify that the problem was not caused by
23 - 96 SUNROOFWJ

CONTROL MODULE
REMOVAL
(1) Move the glass panel to the fully closed posi-
tion.
(2) Remove the A-pillar trim. (Refer to 23 - BODY/
INTERIOR/A-PILLAR TRIM - REMOVAL)
(3) Remove the sun visors. (Refer to 23 - BODY/
INTERIOR/SUN VISOR - REMOVAL)
(4) Remove the overhead console. (Refer to 8 -
ELECTRICAL/OVERHEAD CONSOLE - REMOVAL)
(5) Lower headliner as necessary to gain access to
the sunroof express module.
(6) Disconnect the express module wire harness
connectors.
(7) Remove express module screw.
(8) Remove express module from the keyway by
sliding module towards the center of the vehicle.
INSTALLATION
(1) Insert sunroof express module in the keyway
located in the sunroof module and slide the module
outward to lock it into position.
(2) Install the sunroof express module screw.
(3) Connect the wire connectors to the sunroof
express module.
(4) Install the headliner into position.
(5) Install the overhead console. (Refer to 8 -
ELECTRICAL/OVERHEAD CONSOLE - INSTALLA-
TION)
(6) Install the sun visors. (Refer to 23 - BODY/IN-
TERIOR/SUN VISOR - INSTALLATION)
(7) Install the A-pillar trim. (Refer to 23 - BODY/
INTERIOR/A-PILLAR TRIM - INSTALLATION)
(8) Test sunroof operation, adjust if necessary.
(Refer to 23 - BODY/SUNROOF/GLASS PANEL -
ADJUSTMENTS)
DRIVE MOTOR
REMOVAL
CAUTION: The sunroof system is timed from the
factory so that the motor shuts off automatically
when the sunroof window reaches a certain posi-
tion. Extreme care must be taken when removing
the motor, timing may be thrown off causing possi-
ble damage to the sunroof system. Anytime the
motor is removed from the sunroof assembly the
sunroof glass panel must be in the FULLY CLOSED
POSITION or the unit will be out of timing. The drive
motor cannot be reset to the park position after
being removed.CAUTION: The sunroof motor should only be pow-
ered through the vehicle battery and sunroof wire
harness. Applying power to the sunroof motor leads
will cause failure of the control module.
(1) Move glass panel to the fully closed position.
(2) Remove the A-pillar trim. (Refer to 23 - BODY/
INTERIOR/A-PILLAR TRIM - REMOVAL)
(3) Remove the B-pillar upper trim. (Refer to 23 -
BODY/INTERIOR/B-PILLAR UPPER TRIM -
REMOVAL)
(4) Remove the C-pillar trim. (Refer to 23 - BODY/
INTERIOR/C-PILLAR TRIM - REMOVAL)
(5) Remove the D-pillar trim. (Refer to 23 - BODY/
INTERIOR/D-PILLAR TRIM - REMOVAL)
(6) Remove the sunvisors. (Refer to 23 - BODY/IN-
TERIOR/SUN VISOR - REMOVAL)
(7) Remove the overhead console. (Refer to 8 -
ELECTRICAL/OVERHEAD CONSOLE - REMOVAL)
(8) Disconnect the control switch wire connector.
(9) Remove headliner as necessary to gain access
to sunroof drive motor. Refer to Headliner Removal
and Installation for proper procedures.
(10) Disconnect the drive motor wire harness con-
nectors (Fig. 3).
(11) Remove drive motor fasteners and remove
motor from the sunroof housing.
INSTALLATION
(1) Ensure that the window is in the fully closed
position before mounting the motor. If motor fails
with the window in the open position the sunroof
glass panel timing will have to be timed. The new
motor comes in the fully closed position and with a
gage for setting cable timing. (Refer to 23 - BODY/
SUNROOF/GLASS PANEL - ADJUSTMENTS - TIM-
ING)
(2) Place drive motor into position on the sunroof
housing and install fasteners.
Fig. 3 Sunroof Drive Motor and Express Module
1 - EXPRESS MODULE
2 - SCREW
WJSUNROOF 23 - 101

(6) Push sunshade down until the sunshade clears
the glass then move sunshade rearward behind the
glass panel.
HOUSING ASSEMBLY
REMOVAL
(1) Move glass panel to the fully closed position.
(2) Disconnect battery negative cable.
(3) Recline both front seats.
(4) Remove headliner. (Refer to 23 - BODY/INTE-
RIOR/HEADLINER - REMOVAL)
(5) Disconnect the drain tubes from sunroof hous-
ing (Fig. 7).
(6) Loosen fasteners attaching sunroof housing
assembly.
(7) With the aid of a helper, remove fasteners
attaching sunroof housing assembly to roof panel.
INSTALLATION
(1) Raise the sunroof housing assembly and guide
into position and start fasteners (Fig. 7).
(2) Tighten the fasteners, front to rear, attaching
the sunroof module to roof panel. Tighten the fasten-
ers, front to rear, to 11 N´m (97 in. lbs.) torque.
(3) Connect the drain tubes to the sunroof housing.
(4) Set headliner into position.
(5) Connect express module, drive motor, and con-
trol switch wire connectors.
(6) Test sunroof operation, adjust as necessary.
(7) Finish installing the headliner. (Refer to 23 -
BODY/INTERIOR/HEADLINER - INSTALLATION)
(8) Connect battery negative cable.
Fig. 7 SUNROOF ASSEMBLY
1 - ROOF
2 - DRAIN HOSE
3 - CLAMP
4 - SUNROOF ASSEMBLY
5 - CLAMP
6 - DRAIN HOSE
23 - 104 SUNROOFWJ
SUNSHADE (Continued)

DIAGNOSIS AND TESTING - HEATER
PERFORMANCE
Before performing the following tests, refer to Cool-
ing for the procedures to check the radiator coolant
level, serpentine drive belt tension, radiator air flow
and the radiator fan operation. Also be certain that
the accessory vacuum supply line is connected at the
engine intake manifold for the manual temperature
control system.
MAXIMUM HEATER OUTPUT
Engine coolant is delivered to the heater core
through two heater hoses. With the engine idling at
normal operating temperature, set the temperature
control knob in the full hot position, the mode control
switch knob in the floor heat position, and the blower
motor switch knob in the highest speed position.
Using a test thermometer, check the temperature of
the air being discharged at the HVAC housing floor
outlets. Compare the test thermometer reading to the
Temperature Reference chart.
Temperature Reference
Ambient Air Temperature15.5É C
(60É F)21.1É C
(70É F)26.6É C
(80É F)32.2É C
(90É F)
Minimum Air Temperature at
Floor Outlet62.2É C
(144É F)63.8É C
(147É F)65.5É C
(150É F)67.2É C
(153É F)
If the floor outlet air temperature is too low, refer
to Cooling to check the engine coolant temperature
specifications. Both of the heater hoses should be hot
to the touch. The coolant return heater hose should
be slightly cooler than the coolant supply heater
hose. If the return hose is much cooler than the sup-
ply hose, locate and repair the engine coolant flow
obstruction in the cooling system. Refer to Cooling
for the procedures.
OBSTRUCTED COOLANT FLOW
Possible locations or causes of obstructed coolant
flow:
²Pinched or kinked heater hoses.
²Improper heater hose routing.
²Plugged heater hoses or supply and return ports
at the cooling system connections.
²A plugged heater core.
If proper coolant flow through the cooling system is
verified, and heater outlet air temperature is still
low, a mechanical problem may exist.
MECHANICAL PROBLEMS
Possible locations or causes of insufficient heat:
²An obstructed cowl air intake.
²Obstructed heater system outlets.
²A blend door not functioning properly.
TEMPERATURE CONTROL
If the heater outlet air temperature cannot be
adjusted with the temperature control knob(s) on the
A/C Heater control panel, the following could require
service:
²The A/C heater control.
²The blend door actuator(s).
²The wire harness circuits for the A/C heater con-
trol or the blend door actuator(s).²The blend door(s).
²Improper engine coolant temperature.
STANDARD PROCEDURE - DIODE
REPLACEMENT
(1) Disconnect and isolate the negative battery
cable.
(2) Locate the diode in the harness, and remove
the protective covering.
(3) Remove the diode from the harness, pay atten-
tion to the current flow direction (Fig. 3).
(4) Remove the insulation from the wires in the
harness. Only remove enough insulation to solder in
the new diode.
Fig. 3 DIODE IDENTIFICATION
1 - CURRENT FLOW
2 - BAND AROUND DIODE INDICATES CURRENT FLOW
3 - DIODE AS SHOWN IN THE DIAGRAMS
24 - 6 HEATING & AIR CONDITIONINGWJ
HEATING & AIR CONDITIONING (Continued)

A/C COMPRESSOR CLUTCH
DESCRIPTION
The compressor clutch assembly consists of a sta-
tionary electromagnetic coil, a hub bearing and pul-
ley assembly, and a clutch plate (Fig. 4). The
electromagnetic coil unit and the hub bearing and
pulley assembly are each retained on the nose of the
compressor front housing with snap rings. The clutch
plate is keyed to the compressor shaft and secured
with a bolt.
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 into contact with the 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. The compressor clutch and coil are
the only serviced parts on the compressor.
The compressor clutch engagement is controlled by
several components: the a/c switch on the a/c heater
control panel, the Automatic Zone Control (AZC) con-
trol module (if the vehicle is so equipped), the evap-
orator probe, the a/c high pressure transducer, the
a/c compressor clutch relay, the body control module
(BCM) and the Powertrain Control Module (PCM).
The PCM may delay compressor clutch engagement
for up to thirty seconds. Refer to Electronic Control
Modules for more information on the PCM controls.
DIAGNOSIS AND TESTING - COMPRESSOR
CLUTCH COIL
For circuit descriptions and diagrams, refer to the
appropriate wiring diagrams. The battery must be
fully-charged before performing the following tests.
Refer to Battery for more information.
(1) Connect an ammeter (0 to 10 ampere scale) in
series with the clutch coil terminal. Use a voltmeter
(0 to 20 volt scale) with clip-type leads for measuring
the voltage across the battery and the compressor
clutch coil.
(2) With the a/c heater mode control switch in any
a/c mode, the a/c heater control a/c switch in the ON
position, and the blower motor switch in the lowest
speed position, start the engine and run it at normal
idle.
(3) The compressor clutch coil voltage should read
within 0.2 volts of the battery voltage. If there is
voltage at the clutch coil, but the reading is not
within 0.2 volts of the battery voltage, test the clutch
coil feed circuit for excessive voltage drop and repair
as required. If there is no voltage reading at the
clutch coil, use a DRBIIItscan tool and the appro-
priate diagnostic information for testing of the com-
pressor clutch circuit. The following components
must be checked and repaired as required before you
can complete testing of the clutch coil:
²Fuses in the junction block and the Power Dis-
tribution Center (PDC)
²A/C heater mode control switch
²A/C compressor clutch relay
²A/C high pressure transducer
²A/C evaporator probe
²Powertrain Control Module (PCM)
²Body Control Module (BCM)
(4) The compressor clutch coil is acceptable if the
current draw measured at the clutch coil is 2.0 to 3.9
amperes with the electrical system voltage at 11.5 to
12.5 volts. This should only be checked with the work
area temperature at 21É C (70É F). If system voltage
is more than 12.5 volts, add electrical loads by turn-
ing on electrical accessories until the system voltage
drops below 12.5 volts.
(a) If the clutch coil current reading is four
amperes or more, the coil is shorted and should be
replaced.
(b) If the clutch coil current reading is zero, the
coil is open and should be replaced.
Fig. 4 COMPRESSOR CLUTCH - TYPICAL
1 - CLUTCH PLATE
2 - SHAFT KEY
3 - PULLEY
4 - COIL
5 - CLUTCH SHIMS
6 - SNAP RING
7 - SNAP RING
WJCONTROLS 24 - 13