1995 JEEP YJ instrument panel

REAR WINDOW DEFOGGER
CONTENTS
page page
DIAGNOSIS............................. 1
GENERAL INFORMATION.................. 1SERVICE PROCEDURES................... 3
GENERAL INFORMATION
The electrically-heated rear window defogger is an
available option on XJ (Cherokee), and YJ (Wrangler)
models equipped with the hardtop roof option. Fol-
lowing are general descriptions of the major compo-
nents in the rear window defogger system. Refer to
Group 8W - Wiring Diagrams for complete circuit de-
scriptions and diagrams.
REAR WINDOW GLASS GRID
The heated rear window glass has two electrically-
conductive vertical bus bars and a series of horizon-
tal grid lines made of a silver-ceramic material,
which is baked on and bonded to the inside surface of
the glass. The grid lines and bus bars comprise a
parallel electrical circuit.
When the rear window defogger switch is placed in
the ON position, current is directed to the rear win-
dow grid lines through the bus bars. The grid lines
heat the rear window to clear the surface of fog or
snow. Circuit protection for the heated grid circuit is
provided by fuse 18 (XJ) or fuse 6 (YJ) in the fuse-
block module.
The grid lines and bus bars are highly resistant to
abrasion. However, it is possible for an open to occur
in an individual grid line resulting in no current flow
through the line. The grid lines can be damaged or
scraped off with sharp instruments. Care should be
taken in cleaning the glass or removing foreign ma-
terials, decals or stickers. Normal glass cleaning sol-
vents or hot water used with rags or toweling is
recommended.A repair kit is available to repair the grid lines and
bus bars, or to reinstall the heated glass pigtail
wires.
DEFOGGER SWITCH
The rear window defogger switch is mounted in the
instrument panel left of the steering column for XJ,
or right of the steering column for YJ. The switch cir-
cuit is protected by fuse 8 (XJ) or fuse 9 (YJ) in the
fuseblock module. Actuating the switch energizes the
relay and electronic timer. A light-emitting diode
(LED) in the switch (XJ), or a indicator lamp in the
switch (YJ), illuminates to indicate when the system
is turned on. The defogger switch can not be re-
paired. If faulty, the switch must be replaced.
DEFOGGER RELAY/TIMER
The defogger relay/timer is located in the relay cen-
ter on XJ models, or taped to the instrument panel
wiring harness behind the parking brake pedal in the
left cowl side area on YJ models. When the rear de-
fogger switch is actuated, the rear defogger relay is
energized. This causes current to flow through the
grid circuit for approximately 10 minutes, or until
the rear window defogger switch or ignition switch
are turned off.
DIAGNOSIS
SYSTEM TESTS
Electrically-heated rear window defogger operation
can be confirmed in the following manner:
(1) Turn the ignition switch to the ON position.
(2) Turn rear window defogger control switch ON.
(3) Monitor vehicle voltmeter. With the control
switch ON, a distinct needle deflection should be
noted.(4) The rear window defogger operation can be
checked by feeling the glass. A distinct difference in
temperature between the grid lines and adjacent
clear glass can be detected within 3 to 4 minutes of
operation.
(5) Using a DC voltmeter, contact terminal A (Fig.
1) (passenger side) with the negative lead, and termi-
JREAR WINDOW DEFOGGER 8N - 1

(9) Allow epoxy to cure 24 hours at room tempera-
ture or use heat gun with a 260É-371ÉC (500É-700ÉF)
range for 15 minutes. Hold gun approximately
254mm (10 inches) from repaired area.
(10) After conductive epoxy is properly cured re-
move wedge or clamp from terminal or pigtail and
check operation of rear window defogger. Do not at-
tach connectors until curing is complete.
DEFOGGER SWITCH REMOVE/INSTALL
XJ MODELS
(1) Remove the instrument cluster bezel. Refer to
Group 8E - Instrument Panel and Gauges for proce-
dure.
(2) Remove the switch housing panel.
(3) Unplug the switch connector. Slightly depress
the switch mounting tabs and remove the switch.
(4) Reverse removal procedures to install.
YJ MODELS
(1) Remove 6 bezel screws (Fig. 3).
(2) Slide bezel toward the steering wheel.
(3) Remove 3 screws (Fig. 4).
(4) Unplug the connector from the defogger switch.
(5) Squeeze the ends of the switch to release the
plastic retaining fingers and push outward.
(6) Reverse removal procedures to install.
DEFOGGER RELAY/TIMER REMOVE/INSTALL
XJ MODELS
The rear defogger relay is in the relay center. The
relay center is located on the lower instrument panel
trim cover just right of the steering column.
(1) Remove the rear defogger relay (red) from the
relay center (Fig. 5).
(2) Reverse removal procedures to install.
YJ MODELS
The rear defogger relay is located behind the park-
ing brake pedal in the left cowl side area. Unplug re-
lay from connector and replace with new relay. Be
certain that relay is taped back into place on harness
with plastic cover facing up and terminals facing
down.
Fig. 3 Instrument Bezel Remove/InstallÐYJ
Fig. 4 Defogger Switch Remove/InstallÐYJ
Fig. 5 Rear Defogger RelayÐXJ
8N - 4 REAR WINDOW DEFOGGERJ

POWER LOCKS
CONTENTS
page page
DIAGNOSIS............................. 2
GENERAL INFORMATION.................. 1SERVICE PROCEDURES................... 8
GENERAL INFORMATION
Power locks are optional equipment on XJ (Chero-
kee) models. Power windows and the keyless entry
system are included on vehicles equipped with the
power lock option. All doors and the liftgate can be
locked and unlocked electrically by operating the
switch on either front door panel, or by operating the
lock and unlock buttons of the remote keyless entry
transmitter. The power lock and keyless entry sys-
tems operate with battery power supplied indepen-
dent of the ignition switch.
Following are general descriptions of the major
components in the power lock system. Refer to Group
8W - Wiring Diagrams for complete circuit descrip-
tions and diagrams. Refer to the owner's manual for
more information on the features and use of these
systems.
POWER LOCK SWITCH
The power locks are controlled by a two-way switch
mounted on the trim panel of each front door. The
switch controls battery feed to the lock and unlock
relays. The door lock switches can not be repaired. If
faulty, the entire switch must be replaced.
POWER LOCK/UNLOCK RELAYS
The power lock and unlock relays are located in the
relay center. The relay center is located on the lower
instrument panel reinforcement behind the lower in-
strument panel and just right of the steering column.
The relays respond to inputs from the power lock
switches and the keyless entry module by sending
the correct battery and ground feeds to the lock mo-
tors. The lock and unlock relays can not be repaired.
If faulty, they must be replaced.
POWER LOCK MOTOR
The locks are actuated by a reversible motor
mounted within each door. The motor direction iscontrolled by the battery and ground feeds from the
power lock/unlock relays. The motor can not be re-
paired. If faulty, the entire motor must be replaced.
KEYLESS ENTRY TRANSMITTER
The keyless entry transmitter is equipped with two
buttons labeled Lock and Unlock. It is also designed
to serve as a key fob and is equipped with a key ring.
Each transmitter has a different vehicle access code,
which must be programmed into the memory of the
keyless entry module in the vehicle in order to oper-
ate the locks. The operating range of the infrared
transmitter signal is up to 4.75 meters (15 feet) from
the receiver.
The transmitter operates on two CR1616 3-volt (or
equivalent) batteries. Typical battery life is from one
to two years.
KEYLESS ENTRY MODULE
The keyless entry module is mounted in a housing
on the headliner near the windshield between the
sunvisors, or inside and towards the rear of the over-
head console (if equipped). This module contains the
keyless entry receiver and program logic for the key-
less entry system.
The keyless entry module has a memory function
to retain the vehicle access code of at least one, and
up to four transmitters. The module receives input
from the remote keyless entry transmitter. In re-
sponse to that input, it is programmed to control out-
puts to the lock and unlock relays. The module can
not be repaired and, if faulty, must be replaced.
JPOWER LOCKS 8P - 1

(8) Reverse removal procedures to install. Be sure
to flex housing outward near the keyless entry mod-
ule until the console snaps onto the rear mounting
bracket.
POWER LOCK/UNLOCK RELAY REMOVE/INSTALL
The power lock/unlock relays are located in the re-
lay center. The relay center is located on the lower
instrument panel trim cover just right of the steering
column (Fig. 19).
(1) Remove the appropriate relay from the relay
center.
(2) Reverse removal procedure to install.
Fig. 19 Power Lock/Unlock Relays
8P - 12 POWER LOCKSJ

CHIME/BUZZER WARNING SYSTEMS
CONTENTS
page page
DIAGNOSIS............................. 2
GENERAL INFORMATION.................. 1SERVICE PROCEDURES................... 4
GENERAL INFORMATION
This group covers the buzzer warning system,
which is standard equipment on XJ (Cherokee)/YJ
(Wrangler) models. The system provides an audible
warning to the driver when it monitors the following
conditions:
²key is in ignition switch with the driver's door
open
²head or park lamps are on with driver's door open
(XJ only)
²driver's seat belt is not buckled with ignition
switch in ON position.
Following are general descriptions of the major
components in the buzzer warning system. Refer to
Group 8W - Wiring Diagrams for complete circuit de-
scriptions and diagrams.
BUZZER MODULE
The buzzer module is located in the fuseblock mod-
ule under the left end of the instrument panel. It re-
ceives battery voltage at all times from (fuse 15 - XJ,
fuse 3 - YJ) the fuseblock module. It also receives a
second battery feed (fuse 17 - XJ, fuse 9 - YJ) when
the ignition switch is in the ON or START position.
Other inputs to the module include the driver's door
jamb switch, the driver's seat belt switch, the ignition
key-in switch, and the headlamp switch (XJ only). The
only output of the module is a timed 4 to 8 second feed
to the seat belt reminder lamp in the message center of
the instrument cluster. The timer function begins after
the ignition switch is turned to the ON position.
The buzzer module can not be repaired. If faulty, it
must be replaced.
DRIVER'S DOOR JAMB SWITCH
The driver's door jamb switch is mounted to the
driver's door hinge pillar. The switch closes a path to
ground for the buzzer module through the key-in
switch or headlamp switch (XJ only) when the driv-
er's door is opened, and opens when the driver's door
is closed. This switch can not be repaired. If faulty, it
must be replaced.
IGNITION KEY-IN SWITCH
XJ MODELS
The key-in switch is integral to the ignition switch,
which is mounted on the right side of the steering col-
umn. It closes a path to ground for the buzzer module
when the ignition key is inserted in the ignition lock cyl-
inder and the driver's door jamb switch is closed (door
open). The switch opens when the key is removed from
the ignition lock cylinder. This switch can not be re-
paired. If faulty, the entire ignition switch must be re-
placed. Refer to Group 8D - Ignition Systems for service
procedures.
YJ MODELS
The key-in switch is mounted within the steering col-
umn in the lock cylinder housing. It closes a path to
ground for the buzzer module when the ignition key is
inserted in the ignition lock cylinder and the driver's
door jamb switch is closed (door open). The switch opens
when the key is removed from the ignition lock cylinder.
This switch is available for service replacement. Refer
to Group 19 - Steering for service procedures.
HEADLAMP SWITCH (XJ ONLY)
The headlamp switch is located in the instrument
panel. It closes a path to ground for the buzzer module
when the park or headlamps are on and the driver's
door jamb switch is closed (door open). The switch opens
the ground path when the park and headlamps are
turned off. The headlamp switch can not be repaired. If
faulty, it must be replaced. Refer to Group 8E - Instru-
ment Panel and Gauges for service procedures.
DRIVER'S SEAT BELT SWITCH
The driver's seat belt switch is integral to the driv-
er's seat belt buckle-half assembly. The switch is nor-
mally closed, providing a ground path to the buzzer
module. When the tip-half of the seat belt is inserted
into the seat belt buckle, the switch opens the buzzer
module ground path. The seat belt switch can not be
repaired. If faulty, the entire driver's seat belt buck-
le-half must be replaced. Refer to Group 23 - Body
Components for service procedures.
JCHIME/BUZZER WARNING SYSTEMS 8U - 1

YJ MODELS
(1) Unplug steering column connector from instru-
ment panel wiring. Open driver's door. Check for con-
tinuity between cavity E (black/light blue wire) in
instrument panel half of steering column connector
and a good ground. There should be continuity. If
OK, go to next step. If not OK, repair circuit to driv-
er's door jamb switch as required.
(2) Insert ignition key in ignition lock cylinder.
Check for continuity between cavities E (pink wire)
and F (black wire) in steering column half of connec-
tor. There should be continuity until key is removed.
If OK, go to next step. If not OK, repair steering col-
umn wiring or replace key-in switch as required.
(3) Check for continuity between cavity F (light
blue wire) in instrument panel half of steering col-
umn connector and cavity for terminal 6 of buzzer
module in buzzer module connector. There should be
continuity. If not OK, repair circuit from switch to
buzzer module as required.
HEADLAMP SWITCH (XJ ONLY)
(1) Remove headlamp switch from instrument
panel (refer to Group 8E - Instrument Panel and
Gauges for procedure). Unplug headlamp switch con-
nector. Open driver's door. Check for continuity be-
tween headlamp switch connector cavity with light
blue wire and a good ground. There should be conti-
nuity until driver's door is closed. If OK, go to next
step. If not OK, repair circuit from headlamp switch
to driver's door jamb switch as required.
(2) Check for continuity between headlamp switch
connector cavity with pink/light blue wire and cavity
for terminal 6 of buzzer module in buzzer module
connector. There should be continuity. If OK, go to
next step. If not OK, repair circuit from headlamp
switch to buzzer module as required.
(3) Check continuity between headlamp switch ter-
minal for connector cavity with pink/light blue wire
and terminal for cavity with light blue wire. There
should be no continuity with switch in off position,
and there should be continuity with switch in park
lamps or headlamps on position. If not OK, replace
headlamp switch.
DRIVER'S SEAT BELT SWITCH
(1) Unplug seat belt switch connector on floor un-
der driver's seat riser near seat belt anchor. Check
for continuity between two cavities of seat belt half of
connector. There should be continuity with seat belt
unbuckled, and no continuity with seat belt buckled.
If OK, go to next step. If not OK, replace seat belt
buckle-half assembly.
(2) Check for continuity between cavity with black
wire in harness half of seat belt switch connector and
a good ground. There should be continuity. If OK, go
to next step. If not OK, repair circuit to ground as re-
quired.
(3) Check for continuity between cavity with light
green wire in harness half of seat belt switch connec-
tor and cavity for terminal 4 of buzzer module con-
nector. There should be continuity. If not OK, repair
circuit from seat belt switch connector to buzzer mod-
ule as required.
Fig. 3 Key-In Switch Connector
Fig. 4 Key-In Switch Continuity
JCHIME/BUZZER WARNING SYSTEMS 8U - 3

SERVICE PROCEDURES
Service procedures for components of the buzzer
system can be found in the appropriate group as fol-
lows:
²driver's door jamb switch - refer to Group 8L -
Lamps
²ignition key-in switch (XJ) - refer to Group 8D -
Ignition Systems²ignition key-in switch (YJ) - refer to Group 19 -
Steering
²headlamp switch - refer to Group 8E - Instrument
Panel and Gauges
²driver's seat belt switch - refer to Group 23 - Body
Components.
BUZZER MODULE SCHEMATIC - XJBUZZER MODULE SCHEMATIC - YJ
8U - 4 CHIME/BUZZER WARNING SYSTEMSJ

cuit A142 supplies voltage to the fuel injectors. Each
injector has a separate ground circuit controlled by
the PCM.
Circuit K11 provides ground for injector number
one. The K11 circuit connects to cavity 16 of the
PCM.
Circuit K12 provides ground for injector number
two. The K12 circuit connects to cavity 15 of the
PCM.
Circuit K13 provides ground for injector number
three. The K13 circuit connects to cavity 14 of the
PCM.
Circuit K14 provides ground for injector number
four. The K14 circuit connects to cavity 13 of the
PCM.
On the 4.0L engine, circuit K15 provides ground for
injector number five. The K15 circuit connects to cav-
ity 38 of the PCM.
Also on the 4.0L engine, circuit K16 provides
ground for injector number six. The K16 circuit con-
nects to cavity 58 of the PCM.
HELPFUL INFORMATION
²Circuit A142 splices to supply voltage to the fuel
injectors, ignition coil, PCM, generator.
²For information about fuel injector operation, refer
to Group 14.
IGNITION COIL
When the Automatic Shut Down (ASD) relay con-
tacts close, they connect circuits A14 and A142. Cir-
cuit A142 supplies voltage to the fuel injectors.
Circuit A142 splices to supply voltage to the ignition
coil. The PCM controls the ground path for the igni-
tion coil on circuit K19. Circuit K19 connects to cav-
ity 19 of the PCM.
HELPFUL INFORMATION
Circuit A142 splices to supply voltage to the fuel
injectors, ignition coil, PCM, and generator.
FUEL PUMP RELAY
When the ignition switch is in either the START or
RUN positions, it connects circuit A1 from fuse 6 in
the Power Distribution Center (PDC) to circuit A21.
Circuit A21 supplies battery voltage to the coil side of
the fuel pump relay. The Powertrain Control Module
(PCM) provides ground for the relay on circuit K51.
Circuit K51 connects to cavity 51 of the PCM.
When the PCM grounds the fuel pump relay, con-
tacts inside the relay close and connect circuit A14
from fuse 2 in the PDC to circuit A141. Circuit A141
supplies voltage to the fuel pump motor (part of the
in-tank fuel pump module).
HELPFUL INFORMATION
²Circuit A14 also splices to supply battery voltage
to cavity 3 of the PCM.²Circuit A141 also supplies battery voltage to the
heated oxygen sensor.
FUEL PUMP MODULE
FUEL PUMP MOTOR
When the fuel pump relay contacts close, the relay
supplies voltage to the fuel pump motor. Circuit A141
from the relay supplies voltage to circuit A241. Cir-
cuit A241 connects to circuit F9 in the fuel pump
module harness. Circuit F9 connects to the fuel pump
motor.
Circuit 99 in the fuel pump module harness con-
nects to circuit Z1. Circuit Z1 provides ground for the
fuel pump motor.
FUEL LEVEL SENSOR
The fuel level sensor is a variable resistor. Circuit
G4 connects the fuel level sensor to the fuel gauge in
the instrument cluster. Circuit F87 from fuse 17 in
the fuse block supplies voltage to the fuel gauge. The
fuel level sensor draws voltage from circuit F87
through the fuel gauge on circuit G4. Circuit G4 con-
nects to circuit 57 in the fuel pump module harness.
Circuit 57 connects to the fuel level sensor.
Circuit 99 in the fuel pump module harness con-
nects to circuit Z1. Circuit Z1 provides the ground
path for the fuel level sensor. The grounding point for
circuit Z1 is the left side of the cowl panel.
HELPFUL INFORMATION
As current flows through the coils in the fuel
gauge, it creates a magnetic field. One of the coils in
the gauge receives fixed current. The other coil is
connected to the level sensor. The magnetic field con-
trols the position of the fuel gauge pointer.
The fuel level sensor contains a variable resistor.
As the position of the float arm on the fuel level sen-
sor changes, the resistor changes the current flow
through second coil in the fuel gauge. A change in
current flow alters the magnetic field in the fuel
gauge, which changes the pointer position.
IDLE AIR CONTROL (IAC) MOTOR
The Powertrain Control Module (PCM) operates
the idle air control motor through 4 circuits - K39,
K40, K59, and K60. Each circuit connects to separate
cavities in the PCM connector.
²Circuit K39 connects to cavity 39 of the PCM
²Circuit K40 connects to cavity 40 of the PCM
²Circuit K59 connects to cavity 59 of the PCM
²Circuit K60 connects to cavity 60 of the PCM
VEHICLE SPEED SENSOR
Circuit K7 supplies 8 volts from the Powertrain
Control Module (PCM) to the vehicle speed sensor.
The K7 circuit connects to cavity 7 of the PCM.
8W - 30 - 2 8W-30 FUEL/IGNITIONÐXJ VEHICLESJ