1995 JEEP YJ blower motor

off switch for battery voltage. If no voltage is present
test pressure cut-off switch. If voltage is present go
to next step.
(5) With ohmmeter test harness connector ground
circuit for continuity to ground. If circuit is open, (no
continuity) repair ground circuit. If circuit test OK
and clutch does not engage refer to Powertrain Diag-
nostic Service Manual for A/C clutch circuit test.
AIR CONDITIONING CONTROLSÐYJ VEHICLES
The air conditioning circuit consists of 3 segments;
battery supply, blower motor and compressor clutch.
The 3 segments have a common connection point at
the blower switch.
The power supply circuit extends from the HTR/
FAN fuse to the blower switch. From the blower
switch, battery feed is routed to the blower motor
and compressor clutch circuit.
Refer to Group 8W Wiring Diagrams for wiring
schematic and terminals. Use volt ohmmeter to test
switches.
COMPRESSOR CLUTCH
The clutch assembly consists of a stationary elec-
tromagnetic coil, hub bearing pulley assembly, and
clutch plate. When the coil is energized the plate is
magnetically engaged with the pulley and turns the
compressor shaft.
COMPRESSOR CLUTCH TEST
(1) Unplug clutch coil connector.
(2) Connect jumper wire from battery positive post
to clutch coil connector. The clutch should engage, if
not leave jumper wire connected and go to next step.
(3) Connect jumper wire from clutch coil frame to
chassis ground. The clutch should engage, if not re-
pair clutch coil ground or replace coil.
A/C COMPRESSOR CLUTCH RELAY
The A/C compressor clutch relay controls the 12-
volt source to the A/C clutch. The relay is activated
when the PCM receives a A/C request signal. The
PCM then sends a ground signal to the relay. The re-
lay is activated and sends 12-volts to the clutch coil
which energizes the clutch. The relay is located in
the power distribution center.
COMPRESSOR CLUTCH RELAY TEST
For test procedure refer to Powertrain Diagnostic
Service Manual for A/C clutch relay circuit test.
LOW-PRESSURE HIGH-PRESSURE CUT-OFF
SWITCH
The pressure cut-off switch is located on the filter
drier and is wired in series with compressor clutch.
The switch interrupts the power to the compressorclutch circuit when the pressure drops to 193 kPa (28
psi) or increases above 3100 to 3375 kPa (450 to 490
psi).
PRESSURE CUT-OFF SWITCH TEST
(1) Turn ignition switch to RUN, A/C blower switch
to ON and control set to MAX.
(2) Unplug pressure cut-off switch connector and
test feed circuit from the thermostatic, should be bat-
tery voltage. If not, proceed to thermostatic control
tests.
(3) Test for continuity between the switch termi-
nals. If continuity is not present recover refrigerant
system, replace switch, evacuate and recharge sys-
tem.
THERMOSTATIC CONTROL
Cycling of the compressor and therefore the tem-
perature of the outlet air is regulated by the thermo-
static control. A thermal sensor extends from the
control to the evaporator housing. When the temper-
ature of the evaporator drops below the set tempera-
ture, the thermostatic control opens the clutch
circuit. The circuit remains open until evaporator
temperature rises above the set temperature.
THERMOSTATIC CONTROL TEST
(1) Turn ignition switch to RUN, A/C blower switch
to ON and thermostatic control set to MAX cool.
(2) Test thermostatic control feed terminal from
blower switch, should be battery voltage. If not re-
pair open from blower switch.
(3) Test thermostatic control output terminal to
pressure cut-out switch, should be battery voltage. If
not, replace thermostatic control.
BLOWER MOTOR SWITCH
The blower switch controls blower motor speed.
The blower motor segment consists of the 3 wires
from the blower switch to the motor. Through the
switch, the 3 wires connect the motor brushes to bat-
tery supply. When connected to battery feed, the sep-
arate brushes provide the 3 blower speeds LO, MED,
and HIGH.
BLOWER MOTOR SWITCH TEST
(1) Turn ignition to RUN position.
(2) Test battery side of fuse for battery voltage. If
not, repair open from ignition switch.
(3) Test A/C blower switch feed circuit from fuse
box should be battery voltage. If not, repair open
from fuse panel.
(4) Test A/C blower switch LO terminal with
blower switch in LO, should be battery voltage. If
not, replace switch.
(5) Test A/C blower switch MED terminal with
blower switch in MED, should be battery voltage. If
not, replace switch.
24 - 16 HEATING AND AIR CONDITIONINGJ

(6) Test A/C blower switch HIGH terminal with
blower switch in HIGH, should be battery voltage. If
not, replace switch.
BLOWER MOTOR
The A/C blower motor is attached to the evaporator
housing mounted under the instrument panel. The
motor has a ground wire and 3 wires connect to the
motor brushes. When voltage is applied to the sepa-
rate brushes it provides the 3 blower speeds LO,
MED, and HIGH.
BLOWER MOTOR TEST
Turn ignition switch to RUN for voltage tests and
turn ignition switch to OFF for resistance test.
(1) Test A/C blower motor ground terminal should
be 0 ohms. If not, repair ground circuit.
(2) Test A/C blower motor connector LO terminal
with blower switch in LO, should be battery voltage.
If not repair open from blower switch. If the blower
motor is still inoperative replace motor.
(3) Test A/C blower motor connector MED terminal
with blower switch in MED, should be battery volt-
age. If not repair open from blower switch. If the
blower motor is still inoperative replace motor.
(4) Test A/C blower motor connector HIGH termi-
nal with blower switch in HIGH, should be battery
voltage. If not, repair open from blower switch. If the
blower motor is still inoperative, replace motor.
HEATER DIAGNOSIS
On LHD XJ vehicles a water valve controls coolant
flow to the heater core. The valve is vacuum oper-
ated. When vacuum is applied, the valve opens and
coolant is directed through the heater core and back
to the engine. When the water valve is closed (no
vacuum applied) coolant flow bypasses the heater
core back to the engine.
The heating system receives its battery feed from
the fuse box. On YJ vehicles the feed circuit runs to
the HEATER/OFF switch and then to the BLOWER
switch. On XJ vehicles the feed circuit runs to the
HEAT/MODE switch and then to the BLOWER
switch.
The blower speed is controlled by the blower switch
and blower resistors. With the switch in LO, battery
voltage is supplied to the motor through all of the re-
sistors. The motor runs slowly. When the blower
switch is moved to a higher speed, battery voltage in-
creases to the blower motor which increase its speed.
This is accomplished by bypassing some of the blower
resistors. When the switch is in HI, blower resistors
are bypassed and battery voltage is applied directly
to the blower motor.
The following chart has been developed for quick
reference.
Refer to the Group 8W Wiring Diagrams for com-
plete wiring schematic.
JHEATING AND AIR CONDITIONING 24 - 17

COMPONENT SERVICEÐXJ VEHICLES
INDEX
page page
A/C Recirculating Door Vacuum Motor
Replacement........................... 27
Blower Motor Resistors Replacement.......... 31
Blower Motor/Fan Replacement............... 24
Condenser Filter DrierÐ2.5L Engines.......... 27
CondenserÐ4.0L Engines................... 28
Description.............................. 23
Evaporator Coil........................... 30
Evaporator/Blower Housing.................. 29Expansion Valve.......................... 31
Filter DrierÐ4.0L Engines................... 28
Fin Sensing Cycling Clutch Switch............. 31
Heater and A/C Control Replacement.......... 23
Heater Core............................. 26
Heater Housing Replacement................ 26
Heater/Defroster/Instrument Panel Outlet Vacuum
Motor Replacement...................... 26
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 unit may be removed separately from under
the instrument panel for service.
HEATER AND A/C CONTROL 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).
Fig. 1 Instrument Bezel
Fig. 2 Radio Mounting Screws
Fig. 3 Radio Wiring Harness
JHEATING AND AIR CONDITIONING 24 - 23

(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
2.5L ENGINE
(1) Disconnect the blower motor wires (Fig. 9).
(2) Remove the blower motor mounting bolts (Fig.
10).
(3) Remove the blower motor and fan assembly.
Fig. 4 Control Panel Mounting Screws
Fig. 5 Electrical Connectors
Fig. 6 Vacuum Hose Connector
Fig. 7 Control Cable Locking Tab
24 - 24 HEATING AND AIR CONDITIONINGJ

(4) 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.
4.0L ENGINE
(1) Remove the washer fluid tank.
(2) Disconnect the blower motor wires (Fig. 9).
(3) Remove the blower motor mounting bolts (Fig.
10).
(4) Remove the blower motor and fan assembly.(5) 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. 8 Control Cable and Ring
Fig. 9 Blower Motor Connector
Fig. 10 Blower Motor Mounting Screws
Fig. 11 Blower Fan
JHEATING AND AIR CONDITIONING 24 - 25

HEATER CORE
REVIEW WARNINGS AND CAUTIONS IN
THIS GROUP BEFORE PERFORMING THIS
OPERATION.
REMOVAL
(1) Drain the radiator.
(2) Disconnect heater hoses at heater core tubes.
(3) Remove heater/evaporator housing side cover.
(4) Remove retaining screws and remove heater core
by pulling it straight out of the housing (Fig. 12).
INSTALLATION
(1) Install the heater core into the housing and in-
stall the screws.
(2) Install the evaporator/blower housing side cover.
(3) Install heater hoses to the heater core.
(4) Fill the cooling system.
HEATER HOUSING REPLACEMENT
REVIEW WARNINGS AND CAUTIONS IN
THIS GROUP BEFORE PERFORMING THIS
OPERATION.
REMOVAL
(1) Disconnect negative cable from battery.
(2) Remove center console. Refer to Group 23 body
for procedure.
(3) Remove instrument panel refer to Group 23.
(4) Remove heater hoses.
(5) Recover refrigerant system and remove A/C
lines if equipped.
(6) Remove heater/evaporator housing side cover.
(7) Remove the heater core.
(8) Remove the defroster duct.
(9) Disconnect the vacuum hoses from the heater
core housing vacuum motors.(10) Remove the housing retaining nuts in the en-
gine compartment. Remove the heater core housing.
INSTALLATION
(1) Transfer the vacuum motors, etc. to the re-
placement housing.
(2) Install the heater core housing and heater
housing retaining nuts in the engine compartment.
(3) Install the vacuum hoses.
(4) Install the defroster duct.
(5) Install the heater core.
(6) Install heater/evaporator housing side cover.
(7) Remove heater hoses.
(8) Install A/C lines if equipped and evacuate and
charge refrigerant system.
(9) Remove instrument panel refer to Group 23.
(10) Install center console. Refer to Group 23 body
for procedure.
(11) Install negative cable from battery.
(12) Fill coolant system.
HEATER/DEFROSTER/INSTRUMENT PANEL OUTLET
VACUUM MOTOR REPLACEMENT
(1) Remove center console. Refer to Group 23 body
for procedure.
(2) Remove the lower instrument panel.
(3) Disconnect the vacuum hose(s) from the vac-
uum motor.
(4) Remove the vacuum motor attaching nuts and
remove the vacuum motor from the bracket.
(5) Remove the vacuum motor linkage retaining
clip and remove the rod from the door actuating lever
(Fig. 13).
To install a vacuum motor, reverse the removal
procedure.
Fig. 12 Heater Core
Fig. 13 Vacuum Motor
24 - 26 HEATING AND AIR CONDITIONINGJ

(1) Install the filter drier.
(2) Install and tighten the nut attaching the filter
drier 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) Evacuate and charge the A/C system.
EVAPORATOR/BLOWER HOUSING
REVIEW WARNINGS AND CAUTIONS IN
THIS GROUP BEFORE PERFORMING THIS
OPERATION.
REMOVAL
(1) Disconnect negative cable from battery.
(2) Recover refrigerant from A/C system and dis-
connect A/C lines from the expansion valve.
(3) Disconnect the blower motor wires and the vent
tube.
(4) Remove center console. Refer to Group 23 body
for procedure.
(5) Remove the lower instrument panel.
(6) Disconnect the electrical connections at the
blower motor resistors and cycling clutch switch. Dis-
connect the vacuum hose at the vacuum motor (Fig.
19).
(7) Cut the plastic retaining strap that retains the
evaporator/blower housing to the heater core housing
(Fig. 20).
(8) Disconnect and remove the heater control cable.
(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 en-
gine compartment side of the dash panel (Fig. 21).
Remove evaporator drain tube.
(11) Remove right kick panel and remove the in-
strument panel support bolt.
(12) To disengage housing studs from the dash panel,
gently pull out on the right side of the dash. Then ro-
tate housing downward and toward the rear of the ve-
hicle . Remove the evaporator/blower housing.
INSTALLATION
(1) Position evaporator/blower housing into place,
being sure to line up the housings using the provided
alignment tabs (Figs. 22 and 23).
Fig. 19 Evaporator Housing Components
Fig. 20 Evaporator Housing
Fig. 21 Evaporator Housing Mounting
JHEATING AND AIR CONDITIONING 24 - 29

(2) Install housing retaining screws and rear hous-
ing clip.
CAUTION: When installing evaporator/blower hous-
ing, DO NOT trap wires between fresh air inlet
housing and dash panel.
(3) Install housing retaining nuts on the engine
compartment side of the dash panel.
(4) Connect the A/C hoses to the expansion valve
and connect the heater blower motor wires.
(5) Attach wire connections at blower motor resis-
tors and cycling clutch switch.
(6) Connect vacuum hose at the vacuum motor and
attach heater control cable.
(7) Install instrument panel bolt and kick panel.(8) Install lower instrument panel.
(9) Install the console.
(10) Connect negative cable to battery.
(11) Evacuate and charge A/C system.
(12) Start the vehicle and check for proper opera-
tion at all vacuum motors.
EVAPORATOR COIL
REVIEW WARNINGS AND CAUTIONS IN
THIS GROUP BEFORE PERFORMING THIS
OPERATION.
REMOVAL
(1) Remove the evaporator/blower housing.
(2) Remove the top housing retaining screws. Re-
move the top of the evaporator housing (Fig. 24).
(3) Remove the cycling clutch switch from evapora-
tor.
(4) Remove evaporator retaining screws and lift
the evaporator out of the housing (Fig. 25).
Fig. 22 Evaporator Housing Alignment Tab
Fig. 23 Evaporator Housing
Fig. 24 Top of Housing
Fig. 25 Evaporator
24 - 30 HEATING AND AIR CONDITIONINGJ