air conditioning JEEP YJ 1995 Service And User Guide

nostic Procedures manual for diagnostic information
and operation of the DRB scan tool.
To test operation of the fan relay only, refer to Re-
laysÐOperation/Testing. This can be found in Group
14, Fuel Systems.
REMOVAL
The auxiliary cooling fan is attached to the radia-
tor upper crossmember behind the radiator.
(1) Remove the two fan mounting bolts from radi-
ator upper crossmember (Fig. 43).
(2) Disconnect the electric fan connector.
(3) Lift fan straight up and out of vehicle.
INSTALLATION
(1) Align lower retaining tabs of fan shroud with
slots in bracket at bottom of radiator. Push fan down
into position.
(2) Tighten the mounting bolts to 4 Nzm (31 in.
lbs.) torque.
(3) Connect auxiliary cooling fan electrical connec-
tor.
TRANSMISSION OIL COOLERS
WATER-TO-OIL COOLER
All models equipped with an automatic transmis-
sion are equipped with a transmission oil cooler
mounted internally within the radiator tank. This in-
ternal cooler is supplied as standard equipment on
all models equipped with an automatic transmission.
Transmission oil is cooled when it passes through
this separate cooler. In case of a leak in the internalradiator mounted transmission oil cooler, engine cool-
ant may become mixed with transmission fluid or
transmission fluid may enter engine cooling system.
Both cooling system and transmission should be
drained and inspected if the internal radiator
mounted transmission cooler is leaking.
Also refer to the section on Transmission Air-to-Oil
Coolers. This auxiliary air-to-oil cooler is an option
on most engine packages.
REPLACING WATER-TO-OIL COOLER IN
RADIATOR SIDE TANK
The internal transmission oil cooler located within
the radiator is not serviceable. If it requires service,
the radiator must be replaced.
Once the repaired or replacement radiator has
been installed, fill the cooling system and inspect for
leaks. Refer to the Refilling Cooling System and Test-
ing Cooling System For Leaks sections in this group.
If the transmission operates properly after repairing
the leak, drain the transmission and remove the
transmission oil pan. Inspect for sludge and/or rust.
Inspect for a dirty or plugged inlet filter. If none of
these conditions are found, the transmission and
torque convertor may not require reconditioning. Re-
fer to Group 21 for automatic transmission servicing.
AIR-TO-OIL COOLER
An auxiliary air-to-oil transmission oil cooler is
available with most engine packages.
On XJ and YJ models, the cooler is located in front
of the radiator or A/C condenser (if equipped) and be-
hind the grill (Figs. 44, 45 or 46). It is mounted to
the front frame crossmember.
Fig. 43 Auxiliary Cooling FanÐRemove/InstallÐ
Typical
Fig. 44 Auxiliary Air-To-Oil CoolerÐYJ Models
7 - 36 COOLING SYSTEM SERVICE PROCEDURESJ

The auxiliary oil coolers on all models operate in
conjunction with the internal radiator mounted main
oil cooler. The transmission oil is routed through the
main cooler first, then the auxiliary cooler, before re-
turning to the transmission.REMOVAL/INSTALLATIONÐXJ MODELS
(1) Remove the grill mounting screws and remove
the grill. Refer to Group 23, Body for procedures.
(2) Place a drain pan below the transmission oil
cooler.
(3) Remove the two hose clamps at oil cooler inlet
and outlet tubes (Figs. 45 or 46).
(4) Remove the two oil cooler mounting bolts (Figs.
45 or 46).
(5) Remove the oil cooler from vehicle.
(6) Reverse the preceding operation for installa-
tion. Tighten the two clamps 2 Nzm (15 in. lbs.)
torque. Tighten mounting bolts to 8 Nzm (72 in. lbs.)
torque.
REMOVAL/INSTALLATIONÐYJ MODELS
(1) Remove fan shroud and radiator. Refer to the
Radiators section for procedures.
(2) Remove the air conditioning filter/drier mount-
ing bolts.
WARNING: BEFORE PROCEEDING WITH THE NEXT
STEP, BE SURE TO WEAR SAFETY GLASSES. THE
A/C SYSTEM IS UNDER PRESSURE EVEN WITH
THE ENGINE OFF.
(3) Remove the A/C condenser mounting bolts (Fig.
47).
(4) Carefully tilt the A/C condenser rearward for
access to the auxiliary transmission oil cooler.
(5) Place a drain pan below the oil cooler.
(6) Remove the two hose clamps at oil cooler inlet
and outlet tubes (Fig. 44).
(7) Remove the three oil cooler mounting bolts
(Fig. 44).
(8) Remove the oil cooler from vehicle.
(9) Reverse the preceding operation for installa-
tion. Tighten the two clamps 2 Nzm (15 in. lbs.)
torque. Tighten mounting bolts to 8 Nzm (72 in. lbs.)
torque.
Fig. 45 Auxiliary Air-To-Oil CoolerÐXJ ModelsÐ4.0L
Engine
Fig. 46 Auxiliary Air-To-Oil CoolerÐXJ ModelsÐ2.5L
Engine
Fig. 47 Condenser Mounting BoltsÐYJ Models
JCOOLING SYSTEM SERVICE PROCEDURES 7 - 37

(9) After power steering pump has been tightened
into position, recheck belt tension. Adjust if neces-
sary.
BELT SERVICEÐXJ MODELS WITH RIGHT HAND
DRIVE
The automatic belt tensioner is used only on
XJ models equipped with a 4.0L 6-cylinder en-
gine with right hand drive steering system.
REMOVAL
(1) Attach a socket/wrench to the mounting bolt of
the automatic tensioner pulley (Fig. 7).
(2) Rotate the tensioner assembly clockwise (as
viewed from front) until tension has been relieved
from belt.
(3) Remove belt from idler pulley (Fig. 7) first. Re-
move belt from vehicle.
(4) Check condition and alignment of all pulleys.
INSTALLATION
(1) Position the drive belt over all pulleysexcept
the idler pulley (Fig. 7).
CAUTION: When installing the serpentine accessory
drive belt, the belt must be routed correctly. If not,
the engine may overheat due to the water pump ro-
tating in the wrong direction. Refer to (Fig. 6) for
correct engine belt routing. The correct belt with
the correct length must be used
(2) Attach a socket/wrench to the pulley mounting
bolt of the automatic tensioner (Fig. 7).
(3) Rotate the socket/wrench clockwise (Fig. 7).
Place the belt over the idler pulley. Let tensioner ro-
tate back into place. Remove wrench. Be sure belt is
properly seated in the grooves of all pulleys.
AUTOMATIC BELT TENSIONERÐXJ MODELS WITH
RIGHT HAND DRIVE
The automatic belt tensioner is used only on
XJ models equipped with a 4.0L 6-cylinder en-
gine with right hand drive steering system.
The drive belt is equipped with a spring loaded au-
tomatic belt tensioner (Fig. 10). This belt tensioner
will be used with all belt configurations such as with
or without air conditioning.
REMOVAL
(1) Attach a socket/wrench to the mounting bolt of
the automatic tensioner pulley (Fig. 10).
(2) Rotate the tensioner assembly clockwise (as
viewed from front) until tension has been relieved
from belt.
(3) Remove belt from idler pulley (Fig. 10) first.
Remove belt from automatic tensioner.
(4) Remove tensioner mounting bolt (Fig. 10) from
tensioner bracket. Remove tensioner from vehicle.
Note alignment pin on the back of tensioner.
WARNING: BECAUSE OF HIGH SPRING PRES-
SURE, DO NOT ATTEMPT TO DISASSEMBLE AUTO-
MATIC TENSIONER. UNIT IS SERVICED AS AN
ASSEMBLY (EXCEPT FOR PULLEY).
(5) Remove tensioner pulley bolt. Remove pulley
from tensioner.
Fig. 8 P.S. Pump Rear Mounting BoltsÐTypical
Fig. 9 P.S. Pump Front Mounting Bolt/LocknutÐ
Typical
7 - 42 ENGINE ACCESSORY DRIVE BELTSJ

INSTRUMENT PANEL AND GAUGES
GROUP INDEX
INSTRUMENT PANEL AND GAUGESÐXJ...... 1INSTRUMENT PANEL AND GAUGESÐYJ..... 24
INSTRUMENT PANEL AND GAUGESÐXJ
CONTENTS
page page
DIAGNOSIS............................. 5
GENERAL INFORMATION.................. 1SERVICE PROCEDURES.................. 17
SPECIFICATIONS........................ 23
GENERAL INFORMATION
Following are general descriptions of major instru-
ment panel components. Refer to Group 8W - Wiring
Diagrams for complete circuit descriptions and dia-
grams.
INSTRUMENT PANEL
Modular instrument panel construction allows all
gauges and controls to be serviced from the front of
the panel. In addition, most instrument panel wiring
or heater and air conditioning components can be ac-
cessed without complete instrument panel removal. If
necessary, the instrument panel can be rolled-down
and removed from the vehicle as an assembly.
Removal of the instrument cluster bezel allows ac-
cess to the cluster assembly, most switches, the cli-
mate controls, and the radio. Removal of the cluster
assembly allows access to the individual gauges, illu-
mination and indicator lamp bulbs, printed circuits,
and most wiring.
Removal of the lower instrument panel allows ac-
cess to heater and air conditioning components, the
fuseblock module, the relay center, and other wiring
and electrical components. Those models equipped
with a driver's-side airbag restraint have a knee
blocker and reinforcement behind the driver's-side
lower instrument panel.
The instrument panel layout is mirror image for
left-hand and right-hand drive vehicles. In most
cases, the diagnosis and service procedures found in
this group are applicable to either vehicle. Although,most illustrations represent only the typical left-hand
drive version. Exceptions are clearly identified as
Right-Hand Drive (RHD).
INSTRUMENT CLUSTERS
Two basic instrument cluster options are offered on
XJ (Cherokee) models. One is referred to as a low-
line cluster, and the other is referred to as a high-
line cluster. Each cluster is divided into two areas:
the gauge area, and the tell-tale area. Each area is
served by a separate printed circuit and wiring con-
nector. Some variations of each cluster exist due to
optional equipment and regulatory requirements.
The low-line cluster includes the following gauges:
²fuel gauge
²speedometer/odometer.
The low-line cluster includes provisions for the fol-
lowing indicator lamps:
²anti-lock brake system lamp
²brake warning lamp
²coolant temperature warning lamp
²four-wheel drive indicator lamps
²generator warning lamp
²headlamp high beam indicator lamp
²low oil pressure warning lamp
²low washer fluid warning lamp
²malfunction indicator (Check Engine) lamp
²seat belt reminder lamp
²turn signal indicator lamps
²upshift indicator lamp.
JINSTRUMENT PANEL AND GAUGES 8E - 1

WIRING DIAGRAMS
CONTENTS
page page
8W-01 GENERAL INFORMATIONÐWIRING
DIAGRAMS.................... 8W-01-1
8W-10 FUSE/FUSE BLOCK........... 8W-10-1
8W-11 POWER DISTRIBUTION........ 8W-11-1
8W-15 GROUND DISTRIBUTION....... 8W-15-1
8W-20 CHARGING SYSTEM.......... 8W-20-1
8W-21 STARTING SYSTEM........... 8W-21-1
8W-30 FUEL/IGNITION.............. 8W-30-1
8W-31 TRANSMISSION CONTROLS.... 8W-31-1
8W-32 ANTI-LOCK BRAKES.......... 8W-32-1
8W-33 VEHICLE SPEED CONTROL..... 8W-33-1
8W-40 INSTRUMENT CLUSTER....... 8W-40-1
8W-41 HORN/CIGAR LIGHTER......... 8W-41-1
8W-42 AIR CONDITIONING/HEATER.... 8W-42-1
8W-44 INTERIOR LIGHTING.......... 8W-44-1
8W-47 AUDIO SYSTEM.............. 8W-47-18W-48 HEATED REAR WINDOW....... 8W-48-1
8W-49 OVERHEAD CONSOLE......... 8W-49-1
8W-50 FRONT LIGHTING............. 8W-50-1
8W-51 REAR LIGHTING............. 8W-51-1
8W-52 TURN SIGNALS.............. 8W-52-1
8W-53 WIPERS..................... 8W-53-1
8W-54 TRAILER TOW................ 8W-54-1
8W-60 POWER WINDOWS.......... 8W-60-1
8W-61 POWER DOOR LOCKS......... 8W-61-1
8W-62 POWER MIRRORS............ 8W-62-1
8W-63 POWER SEAT................ 8W-63-1
8W-70 SPLICE INFORMATION........ 8W-70-1
8W-80 CONNECTOR PIN OUTS....... 8W-80-1
8W-90 CONNECTOR LOCATIONS...... 8W-90-1
8W-95 SPLICE LOCATIONS........... 8W-95-1
HOW TO USE THIS GROUP
The purpose of this group is to show the electrical
circuits in a clear, simple fashion and to make trou-
bleshooting easier. Components that work together
are shown together. All electrical components used in
a specific system are shown on one diagram. The feed
for a system is shown at the top of the page. All
wires, connectors, splices, and components are shown
in the flow of current to the bottom of the page. Wir-
ing which is not part of the circuit represented is ref-
erenced to another page/section, where the complete
circuit is shown. In addition, all switches, compo-
nents, and modules are shown in theat rest posi-
tion with the doors closed and the key removed
from the ignition.
If a component is part of several different circuits,
it is shown in the diagram for each. For example, the
headlamp switch is the main part of the exterior
lighting, but it also affects the interior lighting and
the chime warning system.
It is important to realize that no attempt is
made on the diagrams to represent components
and wiring as they appear on the vehicle. For
example, a short piece of wire is treated the
same as a long one. In addition, switches and
other components are shown as simply as pos-
sible, with regard to function only.
The wiring diagram show circuits for all wheel-
bases. If there is a difference in systems or compo-
nents between wheel-bases, an identifier is placed
next to the component.
SECTION IDENTIFICATION
Sections in Group 8W are organized by sub-sys-
tems. The sections contain circuit operation descrip-
tions, helpful information, and system diagrams. The
intention is to organize information by system, con-
sistently from year to year.
CONNECTOR LOCATIONS
Section 8W-90 contains Connector Location illus-
trations. The illustrations contain the connector
number and component identification. Connector Lo-
cation charts in Section 8W-90 reference the illustra-
tion number for components and connectors.
Section 8W-80 shows each connector and the cir-
cuits involved with that connector. The connectors
are identified using the number on the Diagram
pages.
SPLICE LOCATIONS
Splice Location charts in Section 8W-70 show the
entire splice, and provide references to other sections
the splice serves.
Section 8W-95 contains illustrations that show the
general location of the splices in each harness. The
illustrations show the splice by number, and provide
a written location.
JWIRING DIAGRAMSÐXJ VEHICLES 8W - 1 - 1

AIR CONDITIONING/HEATER
CONTENTS
page page
A/C-HEATER SYSTEM...................... 1 HEATERSYSTEM......................... 1
GENERAL INFORMATION
This section of the wiring diagrams is divided into
two sub-sections; Heater, and A/C and Heater. When
referring to the circuit descriptions or wiring dia-
grams, ensure that you use the correct sub-section.
HEATER SYSTEM
BLOWER MOTOR
In the RUN or ACCESSORY position, the ignition
switch connects circuit A1 from fuse 6 in the Power
Distribution Center (PDC) to circuit A48. Circuit A48
supplies battery voltage to fuse 5 in the fuse block.
Fuse 5 supplies power to the heat mode switch on
circuit C7.
Circuit C43 from the heat mode switch splices to
supply voltage to the blower motor switch and the
blower motor resistor block. The blower motor switch
sets blower motor speed to HIGH, M1, M2, or LOW.
When the blower motor switch is in the LOW posi-
tion, circuit C43 from the heat mode supplies voltage
to the resistor block. Voltage does not pass through
the blower motor switch in the LOW position.In the M1 position, the blower motor switch sup-
plies voltage to the resistor block on circuit C4. From
circuit C4, voltage passes through three resistors in
the resistor block to the blower motor on circuit C1.
In the M2 position, the blower motor supplies volt-
age to the resistor block on circuit C6. From circuit
C6 voltage flows through two resistors to the blower
motor on circuit C1.
In the HIGH position, the blower motor switch con-
nects directly to the blower motor on circuit C1. Volt-
age does not pass through the resistor block.
Circuit Z1 provides ground for the blower motor.
A/C-HEATER SYSTEM
GENERAL INFORMATION
Several fuses supply power for the air conditioning/
heater system. In the START or RUN positions, the
ignition switch connects circuit A1 from fuse 6 in the
Power Distribution Center (PDC) to circuit A21. Cir-
cuit A21 powers a bus bar in the PDC that feeds cir-
cuit F12 through fuse 11. Circuit F12 feeds the
contact side of the A/C compressor clutch relay and
the coil side of the radiator fan relay (4.0L engine).
In the RUN or ACCESSORY position, the ignition
switch connects circuit A1 from fuse 11 in the PDC to
circuit A48. Circuit A48 supplies battery voltage to
fuse 5 in the fuse block. Fuse 5 supplies power to the
A/C-Heater control switch on circuit C7.
Fuse 13 in the PDC supplies battery voltage to the
contact side of the radiator fan relay on circuit F141.
Circuit A14 from fuse 15 in the PDC powers PDC
fuse 4.
BLOWER MOTOR
In the RUN or ACCESSORY position, the ignition
switch connects circuit A1 from fuse 6 in the PDC to
circuit A48. Circuit A48 supplies battery voltage to
fuse 5 in the fuse block. Fuse 5 supplies power to the
A/C-Heater control switch on circuit C7.
Circuit C43 from the A/C-heater switch splices to
supply voltage to the blower motor switch and the
blower motor resistor block. The blower motor switch
sets blower motor speed to HIGH, M1, M2, or LOW.
When the blower motor switch is in the LOW posi-
tion, circuit C43 from the A/C-Heater switch supplies
voltage to the resistor block. Voltage does not pass
through the blower motor switch in the LOW position
In the M1 position, the blower motor switch sup-
plies voltage to the resistor block on circuit C4. From
circuit C4, voltage passes through three resistors in
the resistor block to the blower motor on circuit C1.
J8W-42 AIR CONDITIONING/HEATERÐXJ VEHICLES 8W - 42 - 1

In the M2 position, the blower motor supplies volt-
age to the resistor block on circuit C6. From circuit
C6 voltage flows through two resistors to the blower
motor on circuit C1.
In the HIGH position, the blower motor switch con-
nects directly to the blower motor on circuit C1. Volt-
age does not pass through the resistor block.
Circuit Z1 provides ground for the blower motor.
AIR CONDITIONING OPERATION
When the A/C-heater control switch is moved to an
A/C position or the defrost position, the Powertrain
Control Module (PCM) receives the A/C select signal
on circuit C90. Circuit C90 connects to cavity 28 of
the PCM.
Circuit also C90 splices to the low pressure switch
and to supply battery voltage to the coil side of the
A/C compressor clutch relay. If the low pressure
switch is closed, circuit C90 connects to circuit C21.
Circuit C21 supplies battery voltage to the A/C cy-
cling switch. Circuit C91 from the A/C cycling switch
provides the A/C request signal to the PCM. Circuit
C91 connects to cavity 27 of the PCM. Circuit Z1 pro-
vides ground for the A/C cycling switch.
After receiving the A/C request signal, the PCM
supplies ground for the A/C compressor clutch relay
on circuit C13. Circuit F12 from fuse 11 in the PDC
supplies battery voltage to the contact side of the A/C
compressor clutch relay. When the PCM grounds the
relay, the contacts close and connect circuit F12 to
circuit C3. Circuit C3 feeds the A/C compressor
clutch.
Also, after receiving the A/C request signal, the
PCM supplies ground for the coil side of the radiator
fan relay on circuit C27 (4.0L engine). Circuit C27
connects to cavity 31 of the PCM. Circuit F12 sup-
plies battery voltage to the coil side of the relay.
When the PCM grounds the coil side of the radia-
tor fan relay, the contacts close and connects circuit
F141 from fuse 4 in the PDC to circuit C25. Circuit
C25 feeds the radiator fan motor. Circuit Z1 provides
ground for the motor.
HELPFUL INFORMATION
Circuit A14 from PDC fuse 2 powers circuit F141
through fuse 15 in the PDC.
RADIATOR FAN RELAY AND MOTOR
In the START or RUN positions, the ignition
switch connects circuit A1 from fuse 6 in the Power
Distribution Center (PDC) to circuit A21. Circuit A21
powers a bus bar in the PDC that feeds circuit F12
through fuse 11. Circuit F12 feeds the coil side of the
radiator fan relay (4.0L engine).
The PCM supplies ground for the coil side of the
radiator fan relay on circuit C27 (4.0L engine). Cir-
cuit C27 connects to cavity 31 of the PCM.
When the PCM grounds the coil side of the radia-
tor fan relay, the contacts close and connects circuit
F141 from fuse 15 in the PDC to circuit C25. Circuit
C25 feeds the radiator fan motor. Circuit Z1 provides
ground for the radiator fan motor.
HELPFUL INFORMATION
Circuit A14 from PDC fuse 2 powers circuit F141
through fuse 15 in the PDC.
DIAGRAM INDEX
Component Page
A/C Compressor Clutch.....................8W-42-4
A/C Compressor Clutch Relay................8W-42-4
A/C Cycling Switch.......................8W-42-4
A/C Low Pressure Switch...................8W-42-4
A/C Mode Select Switch....................8W-42-5
Blower Motor...........................8W-42-3
Blower Motor Switch......................8W-42-3
Blower Motor Resistor.....................8W-42-3
Fuse 2 (PDC)...........................8W-42-5
Fuse 5 (Fuse Block).....................8W-42-3, 5
Fuse 6 (PDC).........................8W-42-3, 5
Fuse 11 (PDC)..........................8W-42-4
Fuse 15 (PDC)..........................8W-42-5
Heater Mode Switch.......................8W-42-3
Ignition Switch......................8W-42-3, 4, 5
Powertrain Control Module..................8W-42-4
Radiator Fan Motor.......................8W-42-5
Radiator Fan Relay.......................8W-42-5
8W - 42 - 2 8W-42 AIR CONDITIONING/HEATERÐXJ VEHICLESJ

WIRING DIAGRAMS
CONTENTS
page page
8W-01 GENERAL INFORMATIONÐWIRING
DIAGRAMS...................... 8W-01-1
8W-10 FUSE/FUSE BLOCK........... 8W-10-1
8W-11 POWER DISTRIBUTION........ 8W-11-1
8W-15 GROUND DISTRIBUTION....... 8W-15-1
8W-20 CHARGING SYSTEM.......... 8W-20-1
8W-21 STARTING SYSTEM........... 8W-21-1
8W-30 FUEL/IGNITION.............. 8W-30-1
8W-31 TRANSMISSION CONTROLS.... 8W-31-1
8W-32 ANTI-LOCK BRAKES........... 8W-32-1
8W-33 VEHICLE SPEED CONTROL..... 8W-33-1
8W-40 INSTRUMENT CLUSTER....... 8W-40-1
8W-41 HORN/CIGAR LIGHTER........ 8W-41-1
8W-42 AIR CONDITIONING/HEATER.... 8W-42-1
8W-44 INTERIOR LIGHTING.......... 8W-44-1
8W-47 AUDIO SYSTEM.............. 8W-47-18W-48 HEATED REAR WINDOW....... 8W-48-1
8W-49 OVERHEAD CONSOLE.......... 8W-49-1
8W-50 FRONT LIGHTING............ 8W-50-1
8W-51 REAR LIGHTING............. 8W-51-1
8W-52 TURN SIGNALS.............. 8W-52-1
8W-53 WIPERS.................... 8W-53-1
8W-54 TRAILER TOW................ 8W-54-1
8W-60 POWER WINDOWS............ 8W-60-1
8W-61 POWER DOOR LOCKS......... 8W-61-1
8W-62 POWER MIRRORS............ 8W-62-1
8W-63 POWER SEAT................ 8W-63-1
8W-70 SPLICE INFORMATION........ 8W-70-1
8W-80 CONNECTOR PIN OUTS....... 8W-80-1
8W-90 CONNECTOR LOCATIONS...... 8W-90-1
8W-95 SPLICE LOCATIONS........... 8W-95-1
HOW TO USE THIS GROUP
The purpose of this group is to show the electrical
circuits in a clear, simple fashion and to make trou-
bleshooting easier. Components that work together
are shown together. All electrical components used in
a specific system are shown on one diagram. The feed
for a system is shown at the top of the page. All
wires, connectors, splices, and components are shown
in the flow of current to the bottom of the page. Wir-
ing which is not part of the circuit represented is ref-
erenced to another page/section, where the complete
circuit is shown. In addition, all switches, compo-
nents, and modules are shown in theat rest posi-
tion with the doors closed and the key removed
from the ignition.
If a component is part of several different circuits,
it is shown in the diagram for each. For example, the
headlamp switch is the main part of the exterior
lighting, but it also affects the interior lighting and
the chime warning system.
It is important to realize that no attempt is
made on the diagrams to represent components
and wiring as they appear on the vehicle. For
example, a short piece of wire is treated the
same as a long one. In addition, switches and
other components are shown as simply as pos-
sible, with regard to function only.
The wiring diagram show circuits for all wheel-
bases. If there is a difference in systems or compo-
nents between wheel-bases, an identifier is placed
next to the component.
SECTION IDENTIFICATION
Sections in Group 8W are organized by sub-sys-
tems. The sections contain circuit operation descrip-
tions, helpful information, and system diagrams. The
intention is to organize information by system, con-
sistently from year to year.
CONNECTOR LOCATIONS
Section 8W-90 contains Connector Location illus-
trations. The illustrations contain the connector
number and component identification. Connector Lo-
cation charts in Section 8W-90 reference the illustra-
tion number for components and connectors.
Section 8W-80 shows each connector and the cir-
cuits involved with that connector. The connectors
are identified using the number on the Diagram
pages.
SPLICE LOCATIONS
Splice Location charts in Section 8W-70 show the
entire splice, and provide references to other sections
the splice serves.
Section 8W-95 contains illustrations that show the
general location of the splices in each harness. The
illustrations show the splice by number, and provide
a written location.
JWIRING DIAGRAMSÐXJ-RHD 8W - 1 - 1

AIR CONDITIONING/HEATER
CONTENTS
page page
A/C-HEATER SYSTEM...................... 1 HEATERSYSTEM......................... 1
GENERAL INFORMATION
This section of the wiring diagrams is divided into
two sub-sections; Heater, and A/C and Heater. Whenreferring to the circuit descriptions or wiring dia-
grams, ensure that you use the correct sub-section.
HEATER SYSTEM
BLOWER MOTOR
In the RUN or ACCESSORY position, the ignition
switch connects circuit A1 from fuse 6 in the PDC to
circuit A48. Circuit A48 supplies battery voltage to
fuse 4 in the fuse block. Fuse 4 supplies power to the
heat mode switch on circuit C7.
Circuit C43 from the heat mode switch splices to
supply voltage to the blower motor switch and the
blower motor resistor block. The blower motor switch
sets blower motor speed to HIGH, M1, M2, or LOW.
When the blower motor switch is in the LOW posi-
tion, circuit C43 from the heat mode supplies voltage
to the resistor block. Voltage does not pass through
the blower motor switch in the LOW position.
In the M1 position, the blower motor switch sup-
plies voltage to the resistor block on circuit C4. Fromcircuit C4, voltage passes through three resistors in
the resistor block to the blower motor on circuit C1.
In the M2 position, the blower motor supplies volt-
age to the resistor block on circuit C6. From circuit
C6 voltage flows through two resistors to the blower
motor on circuit C1.
In the HIGH position, the blower motor switch con-
nects directly to the blower motor on circuit C1. Volt-
age does not pass through the resistor block in the
HIGH position.
Circuit Z1 provides ground for the blower motor.
DIAGRAM INDEX
AC/HEATER SYSTEM
GENERAL INFORMATION
Several fuses supply power for the air conditioning/
heater system. In the START or RUN positions, the
ignition switch connects circuit A1 from fuse 6 in the
Power Distribution Center (PDC) to circuit A21. Cir-
cuit A21 powers a bus bar in the PDC that feeds cir-
cuit F12 through fuse 11. Circuit F12 feeds the
contact side of the A/C compressor clutch relay and
the coil side of the radiator fan relay.
In the RUN or ACCESSORY position, the ignition
switch connects circuit A1 from fuse 6 in the PDC to
circuit A48. Circuit A48 supplies battery voltage tofuse 4 in the fuse block. Fuse 4 supplies power to the
A/C-Heater control switch on circuit C7.
Fuse 15 in the PDC supplies battery voltage to the
contact side of the radiator fan relay on circuit F141.
Circuit A14 from fuse 2 in the PDC powers PDC fuse
15.
BLOWER MOTOR
In the RUN or ACCESSORY position, the ignition
switch connects circuit A1 from fuse 6 in the PDC to
circuit A48. Circuit A48 supplies battery voltage to
J8W-42 AIR CONDITIONING/HEATERÐXJ-RHD 8W - 42 - 1

fuse 4 in the fuse block. Fuse 4 supplies power to the
A/C-Heater control switch on circuit C7.
Circuit C43 from the A/C-heater switch splices to
supply voltage to the blower motor switch and the
blower motor resistor block. The blower motor switch
sets blower motor speed to HIGH, M1, M2, or LOW.
When the blower motor switch is in the LOW posi-
tion, circuit C43 from the A/C-Heater switch supplies
voltage to the resistor block. Voltage does not pass
through the blower motor switch in the LOW position
In the M1 position, the blower motor switch sup-
plies voltage to the resistor block on circuit C4. From
circuit C4, voltage passes through three resistors in
the resistor block to the blower motor on circuit C1.
In the M2 position, the blower motor supplies volt-
age to the resistor block on circuit C6. From circuit
C6 voltage flows through two resistors to the blower
motor on circuit C1.
In the HIGH position, the blower motor switch con-
nects directly to the blower motor on circuit C1. Volt-
age does not pass through the resistor block in the
HIGH position.
Circuit Z1 provides ground for the blower motor.
AIR CONDITIONING OPERATION
When the A/C-heater control switch is moved to an
A/C position or the defrost position, the Powertrain
Control Module (PCM) receives the A/C select signal
on circuit C90. Circuit C90 connects to cavity 28 of
the PCM.
Circuit also C90 splices to the low pressure switch
and to supply battery voltage to the coil side of the
A/C compressor clutch relay. If the low pressure
switch is closed, circuit C90 connects to circuit C21.
Circuit C21 supplies battery voltage to the A/C cy-
cling switch. Circuit C91 from the A/C cycling switch
provides the A/C request signal to the PCM. Circuit
C91 connects to cavity 27 of the PCM. Circuit Z1 pro-
vides ground for the A/C cycling switch.
After receiving the A/C request signal, the PCM
supplies ground for the A/C compressor clutch relay
on circuit C13. Circuit F12 from fuse 11 in the PDC
supplies battery voltage to the contact side of the A/C
compressor clutch relay. When the PCM grounds the
relay, the contacts close and connect circuit F12 to
circuit C3. Circuit C3 feeds the A/C compressor
clutch.
Also after receiving the A/C request signal, the
PCM supplies ground for the coil side of the radiator
fan relay on circuit C27 (4.0L engine). Circuit C27
connects to cavity 31 of the PCM. Circuit F12 sup-
plies battery voltage to the coil side of the relay.When the PCM grounds the coil side of the radia-
tor fan relay, the contacts close and connect circuit
F141 from fuse 15 in the PDC to circuit C25. Circuit
C25 feeds the radiator fan motor. Circuit Z1 provides
ground for the motor.
HELPFUL INFORMATION
Circuit A14 from PDC fuse 2 powers circuit F141
through fuse 15 in the PDC.
RADIATOR FAN RELAY AND MOTOR
In the START or RUN positions, the ignition
switch connects circuit A1 from fuse 6 in the Power
Distribution Center (PDC) to circuit A21. Circuit A21
powers a bus bar in the PDC that feeds circuit F12
through fuse 11. Circuit F12 feeds the coil side of the
radiator fan relay.
The PCM supplies ground for the coil side of the
radiator fan relay on circuit C27. Circuit C27 con-
nects to cavity 31 of the PCM.
When the PCM grounds the coil side of the radia-
tor fan relay, the contacts close and connect circuit
F141 from fuse 15 in the PDC to circuit C25. Circuit
C25 feeds the radiator fan motor. Circuit Z1 provides
ground for the radiator fan motor.
HELPFUL INFORMATION
Circuit A14 from PDC fuse 2 powers circuit F141
through fuse 15 in the PDC.
DIAGRAM INDEX
Component Page
A/C Compressor Clutch.....................8W-42-4
A/C Compressor Clutch Relay................8W-42-4
A/C Cycling Switch.......................8W-42-4
A/C Low Pressure Switch...................8W-42-4
A/C Mode Select Switch....................8W-42-5
Blower Motor...........................8W-42-3
Blower Motor Switch......................8W-42-3
Blower Motor Resistor.....................8W-42-3
Fuse 2 (PDC)...........................8W-42-5
Fuse 4 (Fuse Block).....................8W-42-3, 5
Fuse 6 (PDC).......................8W-42-3, 4, 5
Fuse 11 (PDC)..........................8W-42-4
Fuse 15 (PDC)..........................8W-42-5
Heater Mode Switch.......................8W-42-3
Ignition Switch......................8W-42-3, 4, 5
Powertrain Control Module..................8W-42-4
Radiator Fan Motor.......................8W-42-5
Radiator Fan Relay.......................8W-42-5
8W - 42 - 2 8W-42 AIR CONDITIONING/HEATERÐXJ-RHDJ