1994 JEEP CHEROKEE relay

²Measure voltage at relay connector terminal 4.
The meter should read battery voltage. If not, repair
open to fuse #18 (XJ), or fuse #9 (YJ).
²Measure voltage at relay connector terminal 5.
The meter should read battery voltage. If not, repair
open from #8 fuse XJ, or fuse #6 YJ.
²Measure resistance between relay connector termi-
nal 1 and left side (driver's side) of defogger grid.
The meter should read zero ohms. If not, repair open
between relay connector and left side of defogger
grid.
²Measure resistance between relay connector termi-
nal 2 and a clean chassis ground. The meter should
read zero ohms. If not, repair open between relay
connector and ground.
²Connect relay connector and measure voltage at
terminal 3. The meter should read approximately 5volts. If not, replace defogger relay.
INDICATOR LAMP
Refer to switch diagram for resistance tests. If val-
ues do not match, replace defogger switch.
DEFOGGER GRID
Turn defogger switch to ON; turn ignition
switch to ON for voltage tests; turn ignition
switch to OFF for resistance tests
²Measure voltage at left side (driver's side) of defog-
ger grid. The meter should read battery voltage. If
not, repair open from defogger relay.
²Measure resistance for right side of defogger grid
to a clean chassis ground. The meter should read
zero ohms. If not, repair open between right side of
defogger grid and ground.
JREAR WINDOW DEFOGGER 8N - 3

XJ
REAR WINDOW DEFOGGER SWITCH
REPLACEMENT
(1) Remove the instrument panel bezel; see 8E-In-
strument Panel and Gauges section for the proce-
dure.
(2) Remove the switch housing panel.
(3) Unplug the switch connector. Slightly depress
the switch mounting tabs and remove the switch.
REAR DEFOGGER RELAY
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. 2).
(2) To install the relay, reverse the removal proce-
dures.
YJ
REAR WINDOW DEFOGGER SWITCH
REPLACEMENT
(1) Remove 6 shroud screws (Fig. 3).
(2) Slide shroud 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) To install, depress the rear window defogger
switch into the bezel until the retaining fingers lock
behind the bezel.
(7) Plug the connector on the switch.(8) Install the bezel with 3 screws.
(9) Install the shroud with 6 screws.
REAR DEFOGGER RELAY
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. 2).
(2) To install the relay, reverse the removal proce-
dures.
Fig. 2 Rear Defogger Relay LocationÐXJ
Fig. 3 Instrument Shroud Removal/InstallationÐYJ
Fig. 4 Defogger SwitchÐYJ
8N - 4 REAR WINDOW DEFOGGERJ

POWER DOOR LOCKS
CONTENTS
page page
KEYLESS ENTRY........................ 8POWER LOCKS......................... 1
POWER LOCKS
INDEX
page page
Actuator Motor Stall Test.................... 6
Description.............................. 1
Diagnosing Power Door Locks............... 1
General................................. 1Liftgate Lock Cylinder Replacement............ 7
Solenoid and Latch Assembly Replacement..... 6
Switch Replacement....................... 6
GENERAL
The door lock actuators, including liftgate, are con-
trolled by two-way switches. To lock the doors, push
down on either switch. To unlock doors from inside
the vehicle push upward on either switch.
The power door locks do not lock or unlock the
doors from outside the vehicle. Insert the key into
the lock cylinder to lock or unlock each individual
door.
DESCRIPTION
The door locks are operated by reversible motors
that receive voltage from fuse #13 in the fuse panel.
Voltage is applied to the driver's side door lock
switch and the passenger's side door lock switch
through the #9 fuse. With the driver's side door lock
switch in LOCK, voltage is applied through the
switch to the door lock relay coil. The relay coil is
energized which closes the circuit from the circuit
breaker to the lock motor. The motor is grounded by
the unlock relay.
The passenger's side door lock window switch oper-
ates the same as the driver's door switch. The volt-
age and ground paths are reversed to unlock the
doors.
The power door lock operates with battery power
and, therefore, is independent of the ignition switch.
DIAGNOSING POWER DOOR LOCKS
If vehicle has Keyless Entry and the door locks op-
erate properly using door switches but do not work
with transmitter, refer to Keyless Entry in this
group.
NO DOOR LOCKS OPERATE USING DOOR
LOCK SWITCHES
(1) Inspect fuse #13. Replace if necessary. If OK,
measure voltage at battery side of fuse. There should
be 12 volts. If not, repair open from Power Distribu-
tion Center.
(2) Remove door switch and measure voltage at
terminal 1. Meter should read battery voltage. If not,
repair open to #9 fuse.
(3) The power window relays are in the relay cen-
ter. The relay center is located on the lower instru-
ment panel trim cover just right of the steering
column (Fig. 1). Remove both relays.
(4) Measure resistance between lock and unlock re-
lay terminal 4 (87A) and ground. Meter should read
zero ohms. If not, repair open to ground.
(5) Measure voltage at terminal 5 (87) of both the
lock and unlock relays. Meter should read battery
voltage. If OK, next step. If not, repair open to cir-
cuit breaker.
(6) Measure resistance at terminal 2 (85) of both
the lock and unlock relays. Meter should read zero
ohms. If not, repair open to ground.
(7) Hold driver's side switch in LOCK position.
Measure voltage at lock relay terminal 1 (86). Meter
should read battery voltage. If OK, next step. If not,
repair open to driver's side switch.
(8) Hold driver's side switch in UNLOCK position.
Measure voltage at unlock relay terminal 1 (86).
Meter should read battery voltage. If OK, next step.
If not, repair open to driver's side switch.
JPOWER DOOR LOCKS 8P - 1

(9) Hold driver's side switch in LOCK position.
Measure voltage at lock relay terminal 3 (30). Meter
should read battery voltage. If OK, next step. If not,
replace lock relay.
(10) Hold driver's side switch in UNLOCK posi-
tion. Measure voltage at unlock relay terminal 3
(30). Meter should read battery voltage. If OK, check
connections and door motor. If not, replace unlock re-
lay.
(11) Repeat procedures for passenger's side switch.
Fig. 1 Door Lock/Unlock Relays
DRIVERS DOOR POWER LOCK SWITCHÐ2-DOOR LEFT HAND DRIVE
8P - 2 POWER DOOR LOCKSJ

(5) Remove latch.
(6) Drill out 2 rivets and remove solenoid.
(7) To install solenoid, reverse the removal proce-
dures.
(8) Tighten latch screws to 9 Nzm (7 ft. lbs.) torque.
KEYLESS ENTRY
INDEX
page page
Diagnosing Power Door Locks............... 9
Door Lock/Unlock Relay Replacement......... 12
Receiver................................ 8
Receiver Service......................... 11
System Description........................ 8System Operation......................... 9
Transmitter.............................. 8
Transmitter Programming................... 9
Transmitter Service........................ 9
SYSTEM DESCRIPTION
The keyless entry system consists of a portable re-
mote control transmitter and a receiver mounted in
the overhead console or between the sun visors. Sys-
tem operation is based on a coded infrared signal
from the transmitter to the receiver. The transmitter
is programmed into the receiver providing the correct
programming sequence is met.
When the keyless entry system is activated, the cor-
responding relay operates to supply voltage to the mo-
tors. The use of either relay determines the polarity of
the voltage that is supplied to the door lock motors.
When the keyless entry system is used, the trans-
mitter sends a signal to the keyless entry module. If
the doors are unlocked, the module activates a tran-
sistor switch to apply voltage to the lock relay coil.
The coil is energized to close the normally open con-
tacts of the lock relay. Battery voltage from the relay
is applied to the door lock motors to lock the doors.
Current flows in the same path to ground as it does
when the master door lock switch is used.When the doors are locked, the keyless entry mod-
ule applies voltage to the unlock relay coil and a
similar action takes places to unlock the doors.
TRANSMITTER
The pocket size, solid state transmitter operates on
(2) 3-volt lithium (CR1616) batteries (Fig. 1). The
transmitter is activated by pressing either the LOCK
or UNLOCK button. This closes the internal contacts
that complete the battery circuit.
The battery voltage activates the transmitter diode
which in turn generates a coded infrared signal. The
signal is transmitted as pulses of infrared light.
If the red LED on the side of the transmitter does
not light when the transmitter is activated, the bat-
teries are low.
RECEIVER
The receiver is in circuit with the electric door lock
system. The coded infrared signal is picked up by the
receiver diode and is shaped, amplified and decoded by
an integrated circuit within the receiver. If the signal
Fig. 10 Latch Assembly Removal/Installation
8P - 8 POWER DOOR LOCKSJ

code received matches the code in the receiver memory
circuit, the receiver triggers the door lock/unlock relays.
The relays complete the circuit to the electric door lock
solenoid to either lock or unlock the doors.
SYSTEM OPERATION
To activate the system, aim the transmitter diode
toward the receiver and press the transmitter signal
button to lock or unlock the doors as desired.
Effective transmitter range is 4.75 meters (15 ft.)
with the transmitter positioned no more than 45 de-
grees from the receiver centerline.
For complete circuit diagrams refer to Group
8W - Wiring Diagrams.
TRANSMITTER PROGRAMMING
Up to 4 Transmitter Identification Codes (TIC's) can
be programed into the receiver at any given time.
(1) Open the driver's door of the vehicle. Leave it
open through the programming procedure.
(2) Move the mechanical door lock lever to the
LOCK position.
(3) Turn the ignition switch to the ON position.
(4) Within 20 seconds, aim a transmitter at the re-
ceiver dome and press the LOCK button for at least
5 seconds. Once the receiver accepts the program-
ming code, the driver's door will unlock.
(5) Once the first transmitter has been pro-
grammed, additional transmitters (up to 4) may be
programmed into the receiver. Within 20 seconds of
the previous transmitter programming, move the me-
chanical door lock lever to the LOCK position. Aimanother transmitter at the receiver dome and press
the LOCK button for at least 5 seconds. The door
lock will cycle again.
(6) To lock the programmed codes into the re-
ceiver, the ignition switch must be turned OFF and
back ON within 20 seconds after programming the
last transmitter's code. At that time, all previous
codes are erased from the module.
DIAGNOSING POWER DOOR LOCKS
NO DOOR LOCKS OPERATE, USING
TRANSMITTER
(1) Measure resistance at keyless entry module
terminal 10. Meter should read zero ohms. If not, re-
pair open to ground.
(2) Measure voltage at keyless entry module termi-
nal 1. Meter should read battery voltage.Battery
voltage must be at least 9 volts for this system to
operate.If not, repair open to #9 fuse.
(3) Jumper test leads keyless entry module termi-
nal 1 to terminal 3. Doors should lock. If OK, replace
module. If not, repair open from terminal 3 to lock
relay terminal 1.
(4) Jumper test leads keyless entry module termi-
nal 1 to terminal 4. Door should unlock. If OK, re-
place module. If not, repair open from terminal 4 to
unlock relay terminal 1.
TRANSMITTER SERVICE
If the receiver malfunctions, only the receiver will
have to be replaced. The new receiver will have to be
reprogrammed. If a transmitter is lost, replace the
transmitter and reprogram the receiver.
Batteries may not be supplied with some re-
placement transmitters. Be sure to check a re-
placement transmitter before attempting to
activate the system.
TRANSMITTER BATTERY REPLACEMENT
(1) Separate transmitter at middle seam (Fig. 2).
Fig. 2 Separate Transmitter Halves
Fig. 1 Keyless Entry Transmitter
JPOWER DOOR LOCKS 8P - 9

(7) Remove screw and printed circuit board.
(8) To install the overhead console, reverse the re-
moval procedures. Be sure to flex housing outward
near the keyless entry receiver until the console
snaps onto the rear mounting bracket.
WITHOUT OVERHEAD CONSOLE
(1) Remove 2 screws attaching receiver housing to
headlining (Fig. 10).
(2) Pull housing toward rear of vehicle to disen-
gage clip.
(3) Disconnect receiver harness connector.
(4) Remove circuit board from housing.
(5) Reverse the removal procedures to install the
receiver.
DOOR LOCK/UNLOCK RELAY REPLACEMENT
The power door lock/unlock relays are in the relay
center. The relay center is located on the lower in-
strument panel trim cover just right of the steering
column (Fig. 11). Remove both relays.
(1) Remove the appropriate relay from the relay
center.
(2) To install the new relay(s) reverse the removal
procedure.
Fig. 8 Keyless Entry Harness Connector
Fig. 9 Keyless Entry Receiver Cover Removal/
Installation
Fig. 10 Remove/Install Keyless Entry Housing
Fig. 11 Door Lock/Unlock Relays
8P - 12 POWER DOOR LOCKSJ

CHIME/BUZZER WARNING SYSTEMS
CONTENTS
page page
GENERAL.............................. 1
IGNITION KEY WARNING SWITCH REPLACEMENT.4OPERATION/DIAGNOSIS.................. 1
GENERAL
The buzzer or optional chime module is mounted on
the left side of the fuse block (above and to the left of
the brake/clutch pedal). The buzzer or chime sounds
an audible warning tone in any of the following con-
ditions:
²Vehicle lights are ON when the ignition has been
switched OFF and the key is removed and then the
driver's door is opened (except YJ).²The key is in the ignition and the driver's door is
open (On some vehicles, the buzzer will not sound if
the ignition switch is in the ON position).
²The ignition is switched ON and the driver's seat
belt is not buckled. Buzzer will quit after 4 to 8 sec-
onds. Besides the buzzer, a seat belt indicator lamp
turns on as a reminder to fasten seat belt.
OPERATION/DIAGNOSIS
OPERATION
Battery voltage for module operation is supplied to
two pins. Voltage is always present at pin 7. Pin 1
receives voltage when the ignition switch is in the
ON or START position.
SEAT BELT WARNING
The seat belt warning system uses both visual and
audible signals. These consist of a buzzer that is part
of a combined seat belt and key warning buzzer and
a red light on the instrument panel.
The system will always illuminate the seat belt
warning lamp for four to eight seconds when the ig-
nition switch is turned to the ON position. Also, only
if the driver does not fasten his seat belt, the buzzer
will sound during the same time interval. Passenger
belts are not connected to the system.
A timed buzzer-relay is used to operate the system
for the time period. It has a time delay mechanism
and buzzer assembly. Only the driver's seat belt
buckle has a switch that is connected to the system.
KEY-IN-IGNITION WARNING
To sound the key-in-ignition warning, the following
must occur:
²the ignition key warning switch must be closed
²the driver's door jamb switch must be closed.
These conditions ground pin 6 of the module. These
switches are closed when the key is in the ignition
and the driver's door is open.On some vehicles the chime/buzzer will not
sound if the door is open and the key is in the
ON position.
LIGHTS-ON WARNING (EXCEPT YJ)
To sound the lights-on warning, the following must
occur:
²the headlamp switch must be closed
²the driver's door jamb switch must be closed.
These conditions ground pin 6 of the module. These
switches are closed when the headlamp switch is ON
and the driver's door is open.
DIAGNOSIS
If the buzzer/chime unit does not operate as de-
scribed, check the two fuses for pins 1 and 7 (Figs. 1
and 2) and replace as required. If the fuses are not
defective, perform the following tests to determine if
the problem is in the module or in the wiring. Using
a flat head screwdriver, release the locking plastic
clip while carefully pulling out the module. Plug in a
known good module and check its operation. If the
problem is not corrected by replacing the module, re-
move the module and continue as follows:
VOLTAGE TESTS
Ignition in ON position, measure between the
following pins and vehicle ground.
²Measure voltage at buzzer/chime module connector
pin 1. Meter should read battery voltage. If not, re-
pair open to ignition switch.
Turn ignition OFF and remove the key from the ig-
nition.
JCHIME/BUZZER WARNING SYSTEMS 8U - 1