2003 JEEP GRAND CHEROKEE wire harness

(10) Allow three to five minutes for the refrigerant
system to stabilize, then take a second set of thermo-
couple measurements. Record the temperature differ-
ence to determine if an additional charge is required.(11) Record the compressor discharge pressure. If
the reading is higher than the pressure shown in the
Compressor Discharge Pressure Chart, the system
could be overcharged. If the reading is equal to, or
lower, than the pressure shown in the chart, continue
with this procedure.
Compressor Discharge Pressure Chart
Ambient
Temperature16ÉC
(60ÉF)21ÉC
(70ÉF)27ÉC
(80ÉF)32ÉC
(90ÉF)38ÉC
(100ÉF)43ÉC
(110ÉF)
Compressor
Discharge
Pressure1378 kPa
(200 psi)1516 kPa
(220 psi)1723 kPa
(250psi)1930 kPa
(280 psi)2206 kPa
(320 psi)2413 kPa
(350 psi)
(12)EXAMPLE:The ambient temperature is 21É
C (70É F). The evaporator inlet tube temperature is
12É C (54É F) and the evaporator outlet tube temper-
ature is 10É C (50É F). Subtract the inlet tube tem-
perature from the outlet tube temperature. The
difference is -2É C (-4É F). With a -2É C (-4É F) tem-
perature differential at 21É C (70É F) ambient tem-
perature, the system is fully charged.
(13) Add enough refrigerant to bring the refriger-
ant system up to a full charge.
(14) Remove the jumper wire from the low pres-
sure cycling clutch switch wire harness connector
and plug the connector back into the switch.
SPECIFICATIONS
CHARGE CAPACITY
The R-134a refrigerant system charge capacity for
this vehicle is 0.765 kilograms (1.687 pounds/27
ounces).
A/C COMPRESSOR
DESCRIPTION
DESCRIPTION - A/C COMPRESSOR
The air conditioning system uses a Nippondenso
10PA17 ten cylinder, double-acting swash plate-type
compressor on all models. This compressor has a
fixed displacement of 170 cubic centimeters (10.374
cubic inches), and has both the suction and discharge
ports located on the cylinder head. A label identifying
the use of R-134a refrigerant is located on the com-
pressor.
DESCRIPTION - HIGH PRESSURE RELIEF
VALVE
A high pressure relief valve is located on the com-
pressor manifold, which is on the side of the com-
pressor. This mechanical valve is designed to vent
refrigerant from the system to protect against dam-
age to the compressor and other system components,
caused by condenser air flow restriction or an over-
charge of refrigerant.
OPERATION
OPERATION - A/C COMPRESSOR
The compressor is driven by the engine through an
electric clutch, drive pulley and belt arrangement.
The compressor is lubricated by refrigerant oil that is
circulated throughout the refrigerant system with the
refrigerant.
The compressor draws in low-pressure refrigerant
vapor from the evaporator through its suction port. It
then compresses the refrigerant into a high-pressure,
high-temperature refrigerant vapor, which is then
pumped to the condenser through the compressor dis-
charge port.
The compressor cannot be repaired. If faulty or
damaged, the entire compressor assembly must be
replaced. The compressor clutch, pulley, and coil, are
available for service.
OPERATION - HIGH PRESSURE RELIEF VALVE
The high pressure relief valve vents the system
when a discharge pressure of 3445 to 4135 kPa (500
to 600 psi) or above is reached. The valve closes
when a minimum discharge pressure of 2756 kPa
(400 psi) is reached.
WJPLUMBING 24 - 57
PLUMBING (Continued)

The high pressure relief valve vents only enough
refrigerant to reduce the system pressure, and then
re-seats itself. The majority of the refrigerant is con-
served in the system. If the valve vents refrigerant, it
does not mean that the valve is faulty.
The high pressure relief valve is a factory-cali-
brated unit. The valve cannot be adjusted or
repaired, and must not be removed or otherwise dis-
turbed. The valve is only serviced as a part of the
compressor assembly.
DIAGNOSIS AND TESTING - COMPRESSOR
NOISE
When investigating an air conditioning related
noise, you must first know the conditions under
which the noise occurs. These conditions include:
weather, vehicle speed, transmission in gear or neu-
tral, engine speed, engine temperature, and any
other special conditions. Noises that develop during
air conditioning operation can often be misleading.
For example: What sounds like a failed front bearing
or connecting rod, may be caused by loose bolts, nuts,
mounting brackets, or a loose compressor clutch
assembly.
Drive belts are speed sensitive. At different engine
speeds and depending upon belt tension, belts can
develop noises that are mistaken for a compressor
noise. Improper belt tension can cause a misleading
noise when the compressor clutch is engaged, which
may not occur when the compressor clutch is disen-
gaged. Check the serpentine drive belt condition and
tension as described in Cooling before beginning this
procedure.
(1) Select a quiet area for testing. Duplicate the
complaint conditions as much as possible. Switch the
compressor on and off several times to clearly iden-
tify the compressor noise. Listen to the compressor
while the clutch is engaged and disengaged. Probe
the compressor with an engine stethoscope or a long
screwdriver with the handle held to your ear to bet-
ter localize the source of the noise.
(2) Loosen all of the compressor mounting hard-
ware and retighten. Tighten the compressor clutch
mounting nut. Be certain that the clutch coil is
mounted securely to the compressor, and that the
clutch plate and pulley are properly aligned and have
the correct air gap. (Refer to 24 - HEATING & AIR
CONDITIONING/CONTROLS/A/C COMPRESSOR
CLUTCH - INSTALLATION)
(3) To duplicate a high-ambient temperature condi-
tion (high head pressure), restrict the air flow
through the condenser. Install a manifold gauge set
to be certain that the discharge pressure does not
exceed 2760 kPa (400 psi).
(4) Check the refrigerant system plumbing for
incorrect routing, rubbing or interference, which cancause unusual noises. Also check the refrigerant lines
for kinks or sharp bends that will restrict refrigerant
flow, which can cause noises. (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING - CAU-
TION - REFRIGERANT HOSES/LINES/TUBES
PRECAUTIONS)
(5) If the noise is from opening and closing of the
high pressure relief valve, reclaim, evacuate, and
recharge the refrigerant system. (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING - STAN-
DARD PROCEDURE - REFRIGERANT RECOVERY)
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - STANDARD PROCEDURE - REFRIG-
ERANT SYSTEM EVACUATE) (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE - REFRIGERANT SYS-
TEM CHARGE)If the high pressure relief valve still
does not seat properly, replace the a/c compressor.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING/A/C COMPRESSOR - REMOVAL)
(6) If the noise is from liquid slugging on the suc-
tion line, check the refrigerant oil level and the
refrigerant system charge. (Refer to 24 - HEATING
& AIR CONDITIONING/PLUMBING/REFRIGER-
ANT OIL - STANDARD PROCEDURE) (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
SPECIFICATIONS - CHARGE CAPACITY).
(7) If the noise continues, replace the compressor
and repeat Step 1.
REMOVAL
REMOVAL
The compressor may be removed and repositioned
without disconnecting the refrigerant lines or dis-
charging the refrigerant system. Discharging is not
necessary if servicing the compressor clutch or clutch
coil, the engine, the cylinder head, or the generator.
WARNING: REVIEW THE WARNINGS AND CAU-
TIONS IN THE FRONT OF THIS SECTION BEFORE
PERFORMING THE FOLLOWING OPERATION.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - WARNING) (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING - CAUTION)
(1) Recover the refrigerant from the system. (Refer
to 24 - HEATING & AIR CONDITIONING/PLUMB-
ING - STANDARD PROCEDURE - REFRIGERANT
RECOVERY)
(2) Disconnect and isolate the battery negative
cable.
(3) Remove the serpentine drive belt. Refer to
Cooling for the procedures.
(4) Unplug the compressor clutch coil wire harness
connector.
24 - 58 PLUMBINGWJ
A/C COMPRESSOR (Continued)

INSTALLATION
INSTALLATION
WARNING: REVIEW THE WARNINGS AND CAU-
TIONS IN THE FRONT OF THIS SECTION BEFORE
PERFORMING THE FOLLOWING OPERATION.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - WARNING) (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING - CAUTION)
Any kinks or sharp bends in the refrigerant plumb-
ing will reduce the capacity of the entire air condi-
tioning system. Kinks and sharp bends reduce the
flow of refrigerant in the system. A good rule for the
flexible hose refrigerant lines is to keep the radius of
all bends at least ten times the diameter of the hose.
In addition, the flexible hose refrigerant lines should
be routed so they are at least 80 millimeters (3
inches) from the exhaust manifold.
High pressures are produced in the refrigerant sys-
tem when the air conditioning compressor is operat-
ing. Extreme care must be exercised to make sure
that each of the refrigerant system connections is
pressure-tight and leak free. It is a good practice to
inspect all flexible hose refrigerant lines at least once
a year to make sure they are in good condition and
properly routed.
NOTE: If a replacement compressor is being
installed, be certain to check the refrigerant oil
level. (Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING/REFRIGERANT OIL - STANDARD PRO-
CEDURE) Use only refrigerant oil of the type
recommended for the compressor in the vehicle.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING/REFRIGERANT OIL - DESCRIPTION)
(1) Install the compressor. Tighten the 4.0L
mounting bolts fastening the compressor to the block
to 45-65 N´m (35-50 ft. lbs.). Tighten the mounting
bolts holding the rear brace to the compressor and
block to 40-55 N´m (30-40 ft. lbs.). Tighten the 4.7L
compressor front mounting screws to 45-65 N´m
(35-50 ft. lbs.), and the rear mounting screws to
35-45 N´m (25-35 ft. lbs.).
(2) Remove the tape or plugs from all of the
opened refrigerant line fittings. Install the suction
line and discharge line fittings to the manifold on the
compressor. Tighten the mounting bolts to 25.4 N´m
(225 in. lbs.).
(3) Install the serpentine drive belt. Refer to Cool-
ing for the procedures.
(4) Plug in the compressor clutch coil wire harness
connector.
(5) Connect the battery negative cable.(6) Evacuate the refrigerant system. (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE - REFRIGERANT SYS-
TEM EVACUATE)
(7) Charge the refrigerant system. (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE - REFRIGERANT SYS-
TEM CHARGE)
INSTALLATION - 2.7L TURBO DIESEL
CAUTION: Check the oil level before installing the
new compressor. (Refer to 24 - HEATING & AIR
CONDITIONING/PLUMBING/REFRIGERANT OIL -
STANDARD PROCEDURE)
WARNING: REVIEW THE WARNINGS AND CAU-
TIONS IN THE FRONT OF THIS SECTION BEFORE
PERFORMING THE FOLLOWING OPERATION.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - WARNING) (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING - CAUTION)
Any kinks or sharp bends in the refrigerant plumb-
ing will reduce the capacity of the entire air condi-
tioning system. Kinks and sharp bends reduce the
flow of refrigerant in the system. A good rule for the
flexible hose refrigerant lines is to keep the radius of
all bends at least ten times the diameter of the hose.
In addition, the flexible hose refrigerant lines should
be routed so they are at least 80 millimeters (3
inches) from the exhaust manifold.
High pressures are produced in the refrigerant sys-
tem when the air conditioning compressor is operat-
ing. Extreme care must be exercised to make sure
that each of the refrigerant system connections is
pressure-tight and leak free. It is a good practice to
inspect all flexible hose refrigerant lines at least once
a year to make sure they are in good condition and
properly routed.
(1) Lift the compressor into position and install
the (4) mounting bolts. Torque the bolts to 41 N´m
(30 ft. lbs.).
(2) Connect the compressor clutch electrical con-
nector.
(3) Install both refrigerant lines on the compressor.
Make certain the sealing 0-rings are free of tears and
well lubricated with R-134a refrigerant oil. Torque
the line retaining bolts to 22 N´m (200 in. lbs.).
(4) Install the front splash shield (if equipped).
(5) Lower the vehicle from the hoist.
(6) Install the accessory drive belt on the compres-
sor clutch. Refer to Cooling for the procedure.
(7) Evacuate the refrigerant system. (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
WJPLUMBING 24 - 61
A/C COMPRESSOR (Continued)

(4) Unplug the clutch coil wire harness connector.
(5) Remove the bolts that secure the viscous
heater to the mounting bracket.
(6) Remove the viscous heater from the mounting
bracket. Support the viscous heater in the engine
compartment while servicing the clutch.
(7) Insert the two pins of the spanner wrench (spe-
cial Tool C-4489 or equivalent) into the holes of the
clutch plate. Hold the clutch plate stationary and
remove the hex nut (Fig. 18).
(8) Remove the clutch plate.
(9) Remove the clutch shims.
(10) Remove the external front housing snap ring
with snap ring pliers (Fig. 19).(11) Install the lip of the rotor puller (Special Tool
C-6141±1 or equivalent) into the snap ring groove
exposed in the previous step, and install the shaft
protector (Special Tool C-6141±2 or equivalent) (Fig.
20).
(12) Install the puller through bolts (Special Tool
C-6461 or equivalent) through the puller flange and
into the jaws of the rotor puller and tighten. Turn
the puller center bolt clockwise until the rotor is free
(Fig. 21).
(13) Remove the screw and retainer from the
clutch coil lead wire harness on the viscous heater
housing.
Fig. 18 CLUTCH NUT REMOVE-typical
1 - CLUTCH PLATE
2 - SPANNER
Fig. 19 EXTERNAL SNAP RING REMOVE- typical
1 - PULLEY
2 - SNAP RING PLIERS
Fig. 20 SHAFT PROTECTOR AND PULLER- typical
1 - PULLER JAW
2 - SHAFT PROTECTOR
Fig. 21 INSTALL PULLER PLATE- typical
1 - PULLER JAW
2 - PULLER
WJPLUMBING 24 - 77
VISCOUS HEATER (Continued)

(14) Remove the snap ring from the hub and
remove the clutch field coil (Fig. 22). Slide the clutch
field coil off of the hub.
INSTALLATION
INSTALLATION
(1) Install Viscous Heater to engine mounting
bracket.
(2) Install the Viscous Heater mounting bolts and
tighten to 33 N´m ( 25 ft. lbs.).
(3) Plug the wiring harness electrical connector to
the Viscous Heater clutch.
(4) Install heater hoses to the Viscous Heater con-
nections.
(5) Install heater hose clamps to Viscous Heater
connections.
(6) Install the engine accessory drive belt(Refer to
7 - COOLING/ACCESSORY DRIVE/DRIVE BELTS -
INSTALLATION).
(7) Refill the engine cooling system(Refer to 7 -
COOLING/ENGINE - STANDARD PROCEDURE).
(8) Reconnect the battery negative cable.
(9) Operate vehicle and check for any coolant
leaks, repair as required.
INSTALLATION - VISCOUS HEATER CLUTCH
(1) Install the clutch field coil and snap ring.
(2) Install the screw and retainer on the clutch coil
lead wire harness on the viscous heater housing.
Tighten the screw to 2.2 N´m (20 in. lbs.)
(3) Align the rotor assembly squarely on the front
housing hub.
(4) Install the rotor bearing asembly with the
installer (Special Tool C-6871 or equalivent). Threadthe installer on the shaft, then turn the nut until the
rotor asembly is seated.
(5) Install the external front housing snap ring
with snap ring pliers. The bevel side of the snap ring
must be facing outward. Press the snap ring to make
sure it is properly seated in the groove.
CAUTION: If the snap ring is not fully seated in the
groove it will vibrate out, resulting in a clutch fail-
ure and severe damage to the front housing of the
compressor.
(6) Install the original clutch shims on the shaft.
(7) Install the clutch plate. Install the shaft hex
nut and tighten to 15±20 N´m (11±15 ft. lbs.).
(8) Check the clutch air gap with a feeler gauge
(Fig. 23). If the gap does not meet specification, add
or substract shims as required. The air gap specifica-
tion if 0.41 to 0.79 millimeters (0.016 to 0.031 inch-
es).
NOTE: The air gap is determined by the spacer
shims. When installing an original, or a new clutch
assembly, try the original shims first. When install-
ing a new clutch (and not having the old shims
available) use a 1.0, 0.50 and 0.13 millimeter (0.040,
0.020 and 0.005 inch) shim from the new clutch
hardware package that is provided with the new
clutch.
(9) Reinstall the viscous heater to the mounting
bracket. Tighten the mounting screws to 33 N´m (25
ft. lbs.).
(10) Reinstall the battery negative cable.
Fig. 22 CLUTCH FIELD COIL SNAP RING REMOVE-
typical
1 - COIL
2 - SNAP RING PLIERS
Fig. 23 CHECK CLUTCH AIR GAP-typical
1 - FEELER GAUGE
24 - 78 PLUMBINGWJ
VISCOUS HEATER (Continued)