1994 JEEP CHEROKEE engine

COMPRESSOR OVERHAUL
INDEX
page page
Compressor............................. 17
Compressor Isolation...................... 17
Description............................. 17Magnetic Clutch......................... 18
Purging Compressor of Air................. 17
DESCRIPTION
The A/C system uses a Sanden compressor. This
compressor is a 7 piston design. Designated the SD-
709, the compressor is mounted on the front right
side of the engine and is driven by a serpentine belt.
System lubrication is provided by 135cc615cc (4.6
cu. in.60.5 cu. in.) of 500 viscosity refrigerant oil.
The clutch used on the compressor consists of 3 ba-
sic components: the pulley, front plate and the field
coil. The pulley and field coil are attached to the
front head of the compressor with tapered snap rings.
The hub is keyed to the compressor shaft and is re-
tained on the shaft with a self-locking nut. Special
service tools are required to remove and install the
clutch plate on the compressor shaft.
COMPRESSOR ISOLATION
It is not necessary to discharge the system for com-
pressor removal. The compressor can be isolated from
the remainder of the system and eliminate the need
for recharging when performing compressor service.
(1) Connect pressure gauge and manifold.
(2) Close both gauge hand valves.
(3) Mid-position both service valves.
WARNING: USE EXTREME CAUTION WHEN THE
ENGINE IS OPERATING. DO NOT STAND IN A DI-
RECT LINE WITH THE FAN. DO NOT PUT YOUR
HANDS NEAR THE PULLEYS, BELTS OR FAN. DO
NOT WEAR LOOSE CLOTHING.
(4) Start the engine and operate the air condition-
ing system.
(5) Turn the suction service valve slowly clockwise
toward the front seated position.
(6) When pressure drops to zero, stop the engine
and compressor and quickly finish front-seating the
suction service valve.
(7) Front-seat the discharge service valve.
(8) Loosen the oil level check plug slowly to re-
lease any internal pressure in the compressor.
The compressor is now isolated from the remainder
of the system.
The service valves can be removed from the com-
pressor.
PURGING COMPRESSOR OF AIR
The compressor must be purged of air whenever it
has been isolated for an oil level check or other ser-
vice procedures without discharging the entire sys-
tem.
(1) Cap the service gauge ports on both of the ser-
vice valves.
(2) Back-seat the suction service valve to allow the
system refrigerant to enter the compressor.
(3) Place the discharge service valve in the mid-po-
sition or cracked-position.
(4) Loosen the discharge service valve gauge port
cap to permit the refrigerant to force any air out of
the compressor.
(5) Back-seat the discharge service valve and
tighten the gauge port cap.
(6) The compressor is now ready for service.
COMPRESSOR
REMOVAL
(1) Isolate the compressor.
(2) Disconnect negative cable from battery.
(3) Disconnect the clutch lead wire.
(4) Remove the discharge and inlet (suction) ser-
vice valves from the compressor. Plug or tape all the
openings.
(5) Remove the serpentine drive belt (refer to
Group 7, Cooling System for the proper procedure).
(6) Remove the bolts and lift the compressor from
the mounting bracket (Figs. 1 and 2).
INSTALLATION
If a replacement compressor is being installed;
check the oil level. Add or subtract oil as neces-
sary and install the magnetic clutch on the com-
pressor.
(1) If the mounting bracket was removed, install
the bracket to the block. Tighten the mounting bolts
to 27 NIm (20 ft. lbs.) torque.
(2) Install the compressor on the mounting
bracket. Tighten the bolts to 27 NIm (20 ft. lbs.)
torque.
(3) Install the serpentine drive belt (refer to Group
7, Cooling System for the proper procedure).
(4) Tighten the serpentine drive belt to the speci-
fied tension.
²New belt tensionÐ800-900 N (180-200 lb-f).
JHEATING AND AIR CONDITIONING 24 - 17

CLIMATE CONTROL SYSTEMÐXJ VEHICLES
INDEX
page page
A/C Recirculating Air Door Vacuum Motor
Replacement.......................... 31
Blower Motor Resistors Replacement......... 35
Blower Motor/Fan Replacement.............. 26
CondenserÐ4.0L Engines.................. 32
Condenser/Receiver DrierÐ2.5L Engines....... 31
Defroster Duct Replacement................ 29
Description............................. 22
Evaporator Coil.......................... 34
Evaporator/Blower Housing................. 33Expansion (H) Valve...................... 35
Heater and A/C Control Panel Replacement.... 26
Heater Control Cable Replacement........... 30
Heater Core............................ 28
Heater Core Housing Replacement........... 29
Heater/Defroster/Instrument Panel Outlet Door
Vacuum Motor Replacement............... 30
Receiver DrierÐ4.0L Engines............... 32
Temperature Control Thermostat............. 35
DESCRIPTION
The Climate Control System combines air condi-
tioning, heating and ventilating capabilities for vehi-
cles equipped with air conditioning. Vehicles without
air conditioning perform heating and ventilating
functions without the air conditioning evaporator.
Both systems consist basically of 2 parts:
²Blower and Air Inlet Assembly
²Heater Core and Air Distribution Assembly
These assemblies, initially installed as a single
unit, may be removed separately from under the in-
strument panel as required for service.
HEATER SYSTEM
The heater system is a blend air type. Outside air
is heated and then blended in varying amounts with
cooler outside air to obtain the desired discharge
temperature. A heater coolant valve provides full
flow to the heater core for all heating modes. The
heater coolant valve remains closed for the ventila-
tion mode, allowing discharge air to approach the
outside ambient air temperature.
AIR CONDITIONING SYSTEM
The air conditioning system has an evaporator to
cool and dehumidify the incoming outside air prior to
blending with the heated air. The evaporator is in
operation during the A/C mode and also in the de-
frost mode for defogging purposes. The evaporator is
not in operation at ambient temperatures below ap-
proximately -1ÉC (30ÉF). To maintain minimum evap-
orator temperature, a fixed thermostat setting switch
cycles the compressor clutch. The blower is operatingthe heater or air conditioning systems, except the
OFF mode. In this mode (OFF) the blower and the
outside air are shut off.
The cooling unit is mounted on the dash panel and
the cooled air is discharged from the instrument
panel registers. The registers are adjusted to provide
general or localized cooling.
SIGHT GLASS
The sight glass is located on top of the receiver/
drier. The sight glass provides a visual check of the
system refrigerant level. A continuous stream of bub-
bles will appear in the sight glass when the system
charge is low. Bubbles will not appear when the sys-
tem is fully charged.
LOW PRESSURE SWITCH
The low pressure switch disengages the magnetic
clutch if the pressure in the system drops below 193
kPa (28 psi). This will occur with a loss in refriger-
ant or with cold ambient temperature.
HEATER VALVE
The heater valve regulates coolant flow to the
heater core. It requires vacuum to shut off flow to
the heater core.
These vehicles are equipped with a bypass-type
heater water valve. When the heater valve is closed,
coolant flow to the heater core is bypassed back to
the engine. When the heater valve is open, coolant is
directed through the heater core and back to the en-
gine.
24 - 22 HEATING AND AIR CONDITIONINGJ

HEATER AND A/C CONTROL PANEL REPLACEMENT
(1) Disconnect negative cable from battery.
(2) Remove the instrument panel bezel attaching
screws and remove the instrument panel bezel (Fig.
1). Bezel is snap fit at locations shown.
(3) Remove the radio attaching screws (Fig. 2).
(4) Disconnect the radio electrical connector,
ground lead and antenna lead (Fig. 3).
(5) Remove the A/C-heater control panel screws
(Fig. 4).(6) Remove the electrical connectors (Fig. 5).
(7) Disconnect the vacuum hoses by releasing the
locking tabs (Fig. 6).
(8) Remove the control cable locking tab by using
a screwdriver to release the tab (Fig. 7).
(9) Remove the ring on the end of the control cable
from the arm on the bottom of the control panel (Fig.
8).
To Install the A/C-heater control panel, reverse the
removal procedures.
BLOWER MOTOR/FAN REPLACEMENT
The blower motor and fan are accessible and
may be removed from the engine compartment.
2.5L ENGINE
(1) Disconnect the blower motor wires (Fig. 9).
(2) Remove the blower motor and fan assembly
mounting screws (Fig. 10).
(3) Remove the blower motor and fan assembly.
(4) Remove the blower motor fan from the motor
shaft for access to the motor attaching nuts (Fig. 11).
Fig. 1 Instrument Bezel
Fig. 2 Radio Mounting Screws
Fig. 3 Radio Wiring Harness
Fig. 4 Control Panel Mounting Screws
24 - 26 HEATING AND AIR CONDITIONINGJ

To install the blower fan and motor, reverse the re-
moval procedures.
4.0L ENGINE
(1) Remove the coolant bottle retaining strap and
move bottle aside.
(2) Remove the coolant bottle bracket.
(3) Remove the anti-lock brake pump and bracket
as an assembly (if equipped) and move the pump
aside.
(4) Disconnect the blower motor wires (Fig. 9).(5) Remove the blower motor and fan assembly
mounting screws (Fig. 10).
(6) Remove the blower motor and fan assembly.
(7) Remove the blower motor fan from the motor
shaft for access to the motor attaching nuts (Fig. 11).
To install the blower fan and motor, reverse the re-
moval procedures.The ears (A) and (B) of the re-
tainer clip must be over the flat surface on the
motor shaft (Fig. 11).
Fig. 5 Electrical Connectors
Fig. 6 Vacuum Hose Connector
Fig. 7 Control Cable Locking Tab
Fig. 8 Control Cable and Ring
JHEATING AND AIR CONDITIONING 24 - 27

(4) Connect the heater hoses to the heater core.
(5) Fill the cooling system.
HEATER CORE HOUSING REPLACEMENT
(1) Remove the evaporator/blower housing.
(2) Remove the heater core.
(3) Remove the defroster duct.
(4) Disconnect the vacuum hoses from the heater
core housing vacuum motors.
(5) Remove the heater housing retaining nuts in
the engine compartment. Remove the heater core
housing.
(6) Transfer the vacuum motors, etc. to the re-
placement housing.
To install the heater core housing, reverse the re-
moval procedure.
DEFROSTER DUCT REPLACEMENT
REMOVAL
(1) Disconnect negative cable from battery.
(2) If equipped with center console remove the con-
sole as follows:
(a) MANUAL TRANSMISSIONÐRemove shift
knob, boot and bezel.
(b) AUTOMATIC TRANSMISSIONÐRemove
shift handle by pulling up. Remove the shift bezel.
(c) POWER MIRRORSÐPry mirror switch out of
console cover (Fig. 13). Disconnect switch connector
(Fig. 14).
(d) Remove console cover screws (Fig. 14).
(e) Remove console cover from base (Fig. 15).
(f) Remove console base (Fig. 15).
(3) Remove the lower instrument panel.
(4) Remove the left kick panel.
(5) Remove the instrument panel retaining bolt.
(6) Remove the instrument panel retaining bolts
located at the steering column.
(7) Remove the right and left A-pillar trim.(8) Remove the defroster bezel attaching screws
and bezel (Fig. 16).
Fig. 13 Power Mirror Switch
Fig. 14 Console Cover Screws and Power Mirror
Switch Connector
Fig. 15 Console Cover and Base
JHEATING AND AIR CONDITIONING 24 - 29

(5) Remove the vacuum motor linkage retaining
clip and remove the rod from the door actuating le-
ver (Fig. 18).
To install a vacuum motor, reverse the removal
procedure.
A/C RECIRCULATING AIR DOOR VACUUM MOTOR
REPLACEMENT
(1) Remove the vacuum motor cover (Fig. 19).
(2) Disconnect the vacuum hose (Fig. 20).(3) Remove the actuating rod clip and disengage
the rod from the door lever.
(4) Remove the vacuum motor retaining nuts and
then remove the vacuum motor.
To install the motor, reverse the removal proce-
dures.
CONDENSER/RECEIVER DRIERÐ2.5L ENGINES
REMOVAL
(1) Drain the radiator.
(2) Disconnect the fan shroud and the radiator
hoses.
(3) Disconnect the transmission cooler lines (if
equipped with automatic transmission).
(4) Evacuate the A/C system. Disconnect the A/C
hoses from the condenser.
(5) Unplug the harness from the low pressure
switch (Fig. 21).
(6) Remove the radiator and condenser as an as-
sembly.
(7) Remove the retaining bolts and separate the
condenser from the radiator.
(8) Remove the receiver/drier from the condenser.
Keep receiver/drier openings plugged at all
times to prevent moisture from entering the re-
ceiver/drier.
INSPECTION
When servicing a condenser for a leak at the bot-
tom, inspect the lower crossmember for an ID tag.
This tag may rub against the condenser. If the con-
dition exists, remove the tag prior to installing a new
condenser.
Fig. 18 Vacuum Motor
Fig. 19 Vacuum Door Motor Cover
Fig. 20 Vacuum Door Motor
JHEATING AND AIR CONDITIONING 24 - 31

INSTALLATION
(1) Remove the plugs from the receiver/drier open-
ings. Install receiver/drier into the condenser.
(2) Install the condenser to the radiator. Tighten
the retaining bolts.
(3) Install the radiator and condenser as an assem-
bly (refer to Group 7, Cooling System for the proper
procedure).
(4) Plug the harness into the low pressure switch
(Fig. 21).
(5) Connect the A/C hoses to the condenser.
(6) Connect the transmission cooler lines (if
equipped with automatic transmission).
(7) Connect the fan shroud and the radiator hoses.
(8) Add 30 ml (1 fluid oz.) of refrigerant oil to the
system if the condenser was replaced.
(9) Fill the cooling system.
(10) Charge the A/C system.
CONDENSERÐ4.0L ENGINES
REMOVAL
(1) Disconnect the fan shroud and electric fan from
the radiator.
(2) Remove the upper crossmember and bracket.
(3) Evacuate the A/C system, disconnect the A/C
hoses from the condenser and plug the openings.
(4) Remove the attaching hardware and brackets
securing the condenser to the radiator.
(5) Remove the condenser.
INSPECTION
When servicing a condenser for a leak at the bot-
tom, inspect the lower crossmember for an ID tag.
This tag may rub against the condenser. If the con-dition exists, remove the tag prior to installing a new
condenser.
INSTALLATION
(1) Install the condenser.
(2) Remove the plugs from the openings. Connect
the A/C hoses to the condenser.
(3) Install the upper crossmember and bracket.
(4) Connect the fan shroud and electric fan to the
radiator.
(5) Add 30 ml (1 fluid oz.) of refrigerant oil to the
A/C system if the condenser was replaced.
(6) Charge the A/C system.
RECEIVER DRIERÐ4.0L ENGINES
REMOVAL
(1) Evacuate the A/C system, disconnect the A/C
hoses from the receiver dryer and plug the openings
(Fig. 22).
(2) Unplug the harness from the low pressure
switch.
(3) Remove the nut attaching the receiver dryer to
the side sill weld stud.
(4) Remove the receiver dryer.
INSTALLATION
(1) Install the receiver dryer.
(2) Install and tighten the nut attaching the re-
ceiver dryer to the side sill weld stud.
(3) Plug the harness to the low pressure switch.
(4) Remove the plugs the openings. Connect the
A/C hoses to the receiver dryer.
(5) Charge the A/C system.
Fig. 21 Condenser Receiver DrierÐ2.5L Engine
Fig. 22 Receiver DryerÐ4.0L Engine
24 - 32 HEATING AND AIR CONDITIONINGJ

EVAPORATOR/BLOWER HOUSING
REMOVAL
(1) Disconnect negative cable from battery.
(2) Discharge the A/C system as described in this
section and disconnect the A/C hoses from the expan-
sion valve.
(3) Disconnect the blower motor wires and the vent
tube.
(4) If equipped with center console remove the con-
sole as follows:
(a) MANUAL TRANSMISSIONÐRemove shift
knob, boot and bezel.
(b) AUTOMATIC TRANSMISSIONÐRemove
shift handle by pulling up. Remove the shift bezel.
(c) POWER MIRRORSÐPry mirror switch out of
console cover (Fig. 13) and disconnect switch con-
nector (Fig. 14).
(d) Remove console cover screws (Fig. 14).
(e) Remove console cover from base (Fig. 15).
(f) Remove console base.
(5) Remove the lower instrument panel.
(6) Disconnect the electrical connections at the
blower motor resistors and the A/C thermostat. Dis-
connect the vacuum hose at the vacuum motor (Fig.
23).
(7) Cut the plastic retaining strap that retains the
evaporator/blower housing to the heater core housing
(Fig. 24).
(8) Disconnect and remove the heater control ca-
ble.
(9) Remove the clip at the rear of the blower hous-
ing flange and remove the retaining screws.(10) Remove the housing attaching nuts from the
studs on the engine compartment side of the dash
panel (Fig. 25). Remove the evaporator drain tube.
(11) Remove the right kick panel and then remove
the instrument panel support bolt.
(12) To disengage the housing studs from the dash
panel, gently pull out on the right side of the dash.
Then rotate the housing downward and toward the
rear of the vehicle. Remove the evaporator/blower
housing.
Fig. 23 Evaporator Housing Components
Fig. 24 Evaporator Housing
Fig. 25 Evaporator Housing Mounting
JHEATING AND AIR CONDITIONING 24 - 33