relay JEEP CHEROKEE 1994 Service Service Manual

HORNS
CONTENTS
page page
GENERAL INFORMATION.................. 1
HORN SWITCH (HORN PAD) REPLACEMENT . . 3
TORQUE SPECIFICATIONS................. 3XJ ..................................... 1
YJ ..................................... 2
GENERAL INFORMATION
For XJ/YJ vehicles battery voltage is applied to the
horn relay through a fuse.
When the horn switch is depressed, the horn relay
is grounded, pulling the contact closed and providing
battery voltage to the horns.
A slip ring and brush arrangement in the steering
wheel allows the switch circuit to maintain contact
while allowing rotation of the steering wheel.On XJ models, a cadmium-plated ground
screw is used to attach the horn(s) to the body.
Do not substitute other types of ground screws
as they may become corroded and cause a loss
of ground.
XJ
REPLACEMENT
(1) Raise and support the vehicle.
(2) Remove the splash shield.
(3) Remove horn mounting bolt and horn mounted
on the drivers side (Fig. 1).
(4) Remove wire from horn.
(5) To install horn, reverse the removal proce-
dures.
DIAGNOSIS AND REPAIR
Refer to Group 8W - Wiring Diagrams for a com-
plete circuit diagram.
HORN RELAY
²Inspect 25 amp, #11 fuse. Replace fuse as re-
quired.
²Depress horn switch. The relay contacts should
click. If OK, go to HORNS. If not, go to next step.
²Remove the horn relay located in the relay center.
The relay center is on the lower instrument panel
trim cover just right of the steering column (Fig. 2).
There should be 12 volts at relay connector pins 1
and 2. If not, repair open in circuit to relay.
²Depress horn switch. Measure resistance between
relay connector pin 5 and ground. The meter should
read zero ohms. If not, repair open to horn switch
ground.
²Measure resistance between relay connector pin 4
and ground. The meter should read almost zero ohms
(horn resistance) If OK, replace relay. If not, repair
open in circuit between relay and horns.
Fig. 1 Drivers Side Horn
JHORNS 8G - 1

HORNS
²Disconnect horn connector. Depress horn switch.
There should be 12 volts at the horn connector. If
not, repair open to relay.
²Measure the resistance between the horn bracket
and chassis ground. The meter should read zero
ohms. If not, check mounting screw for corrosion and
replace as necessary.
²If above steps do not identify a problem, replace
horns.
YJ
Wrangler/YJ horns are located on the drivers side
inner fender.
REPLACEMENT
(1) Disconnect wire harness connector from the
horn (Fig. 3).
(2) Remove horn and bracket mounting bolt. Horn
and bracket are removed as an assembly.
(3) To install, reverse the removal procedures.
DIAGNOSIS AND REPAIR
Refer to Group 8W - Wiring Diagrams for a com-
plete circuit diagram.
HORN RELAY
²Inspect 10 amp fuse, #F15, located in the power
distribution center (PDC). Replace fuse as required.
²Depress horn switch. The relay contacts should
click. If OK, go to HORN. If not, go to next step.
²Remove relay from PDC. There should be 12 volts
at cavities 2 and 5. If not, repair open in circuit to
relay.
²Depress horn switch. Measure resistance between
relay cavity 1 and ground. The meter should read
zero ohms. If not, repair open to horn switch ground.
²Measure resistance between relay cavity 4 and
ground. The meter should read almost zero ohms
(horn resistance) If OK, replace relay. If not, repair
open in circuit between relay and horn.
HORN
²Disconnect horn connector. Depress horn switch.
There should be 12 volts at the horn connector pin A.
If not, repair open to relay.
²Measure the resistance between the horn connec-
tor pin B and chassis ground. The meter should read
zero ohms. If not, repair open to ground.
²If above steps do not identify a problem, replace
horn.
Fig. 2 Horn Relay
Fig. 3 Horn Removal/InstallationÐYJ
8G - 2 HORNSJ

FOG LAMP SERVICE INFORMATION
Fog lamps can be operatedONLYwhen the head-
lamps are on LOW beam. If the headlamps are
switched to HIGH beam, the fog lamps will not oper-
ate.
Also, the fog lamps ON display on the switch will:
²be illuminated when the headlamps are switched
to LOW beam; and
²be extinguished when the headlamps are switched
to HIGH beam.
FOG LAMP TROUBLE DIAGNOSIS
ONE FOG LAMP INOPERATIVE
(1) Place the headlamp switch in the full ON posi-
tion, the dimmer switch in the LOW beam position
and the fog lamp switch in the ON position.
(2) Disconnect the applicable fog lamp wire har-
ness connector (Fig. 33).
(3) Measure the resistance between the lamp con-
nector terminals. The ohmmeter should indicate zero
ohms. If not OK, replace the bulb.
(4) Measure the resistance between the wire har-
ness connector ground terminal and vehicle body
ground. The ohmmeter should indicate zero ohms. If
not OK, repair the open circuit in the wire harness
to vehicle body ground.
(5) Measure the voltage between the wire harness
connector voltage supply terminal and body ground.
The voltmeter should indicate battery voltage. If not
OK, repair the open circuit in the wire harness that
leads to the source of battery voltage.
BOTH FOG LAMPS INOPERATIVE
(1) Place headlamp switch in the full ON position.The dimmer switch in the LOW beam position. The
fog lamp switch in the ON position.
(2) Measure the voltage between the fog lamp
switch wire harness connector terminal B and vehi-
cle body ground. The voltmeter should indicate bat-
tery voltage. If not OK, repair the open circuit in the
wire harness that leads to the headlamp dimmer
switch circuit.
(3) Measure the voltage between the fog lamp
switch connector terminal C and vehicle body
ground. The voltmeter should indicate battery volt-
age. If not OK, replace the fog lamp switch.
(4) Measure the voltage between the fog lamp re-
lay connector terminal 1 and vehicle body ground.
The voltmeter should indicate battery voltage. If not
OK, repair the open circuit in the wire harness that
leads to the power distribution center/PDC.
(5) Measure the voltage between the fog lamp re-
lay connector terminal 5 and vehicle body ground.
The voltmeter should indicate battery voltage. If not
OK, repair the open circuit in the wire harness that
leads to the fog lamp switch.
(6) Measure the voltage between the fog lamp re-
lay connector terminal 2 and vehicle body ground.
The voltmeter should indicate battery voltage. If not
OK, repair the open circuit in the wire harness that
leads to vehicle body ground.
(7) Measure the voltage between the fog lamp re-
lay connector terminal 4 and vehicle body ground.
The voltmeter should indicate battery voltage. If not
OK, replace the relay.
FOG LAMP BEAM ADJUSTMENT
Use an ``aiming'' screen for fog lamp beam aim ad-
justment.
PREPARATION
Prior to adjustment, the following preparation is
required.
Fig. 32 Replacing CHMSL Bulb
Fig. 33 Fog Lamp & Wire Harness ConnectorÐXJ
Vehicles
8L - 12 LAMPSJ

(3) For XJ vehicles, position the bezel and the lens
on the lamp housing. Install the screws that attach
the bezel and lens to the lamp housing. Tighten the
screws securely.
(4) For YJ vehicles, position the stone shield and
reflector on the lamp housing. Install the screws that
attach the stone shield and the reflector to the lamp
housing. Tighten the screws securely.
FOG LAMP SWITCH REPLACEMENT
REMOVALÐXJ VEHICLES
The fog lamp switch is located on the instrument
panel at the left of the steering column.
(1) Remove instrument panel bezel attaching
screws and remove the bezel (Fig. 37).
(2) Remove the fog lamp switch cover.
(3) Disconnect the wire harness connector from the
switch.
(4) Squeeze the tabs on the side of the switch and
remove the switch from the instrument panel cavity.
INSTALLATIONÐXJ VEHICLES
(1) Squeeze the tabs on the side of the fog lamp
switch and insert the switch in the instrument panel
cavity.
(2) Connect the wire harness connector to the
switch.
(3) Install the fog lamp switch cover.
(4) Position the bezel on the instrument panel and
install the attaching screws. Tighten the screws se-
curely.
REMOVALÐYJ VEHICLES
The fog lamp switch is located on the instrument
panel at the right of the steering column. The fog
lamp circuit relay is located below the left headlamp.
(1) Disconnect the battery negative cable.
(2) Remove the I/P shroud retaining screws (Fig.
36).(3) Move the I/P shroud toward the steering wheel.
(4) Apply upward force to the I/P shroud and
downward force to the indicator panel. This will re-
lease the indicator panel holding tabs (Fig. 39).
(5) Remove the shroud from the instrument panel.
(6) Remove the fog lamp switch retaining screws.
(7) Disconnect the wire harness connector from the
fog lamp switch.
(8) Remove the fog lamp switch from the instru-
ment panel cavity.
Fig. 37 Instrument Panel BezelÐXJ Vehicles
Fig. 38 Instrument Panel ShroudÐYJ Vehicles
Fig. 39 Indicator Panel Holding TabsÐYJ Vehicles
8L - 14 LAMPSJ

(3) Measure the voltage between the pink wire on
the switch connector and vehicle body ground. The
voltmeter should indicate battery voltage. If not OK,
repair the open circuit in the wire harness from the
splice.
(4) Connect a jumper wire from the ground side of
the switch to a good vehicle body ground. Measure
the resistance to vehicle body ground. The ohmmeter
should indicate zero ohms. If not, repair the open cir-
cuit in the wire harness to vehicle body ground.
DOME LAMP REPLACEMENT
REMOVALÐXJ VEHICLES
(1) Remove the dome lamp lens by squeezing it at
both sides. This will separate the lens retainer tabs
from the lamp housing shoulders.
(2) Pull the lens downward to remove it from the
lamp housing.
(3) Remove the lamp housing retainer clips (Fig.
2).
(4) Disconnect the wire harness connector.
(5) Remove the lamp housing from the headliner
cavity.
INSTALLATIONÐXJ VEHICLES
(1) Position the dome lamp housing at the head-
liner cavity.
(2) Connect the wire harness connector.
(3) Install the lamp housing retainer clips (Fig. 2).
(4) Position the lens at the lamp housing and force
it upward into the housing until the retainer tabs
are seated on the lamp housing shoulders.
HARDTOP DOME/CARGO LAMP BULB
REPLACEMENTÐYJ VEHICLES
REMOVAL
(1) Remove the dome/cargo lamp lens by squeezing
it at both sides. This will separate the lens retainer
tabs from the lamp housing shoulders (Fig. 3).
(2) Remove the lens from the lamp housing.
(3) Pull the bulb straight out to remove from the
bulb holder.
INSTALLATION
(1) Insert the replacement bulb in the bulb holder.
(2) Position lens at the lamp housing and force it
into the housing until the retainer tabs are seated.
OVERHEAD CONSOLEÐXJ VEHICLES
MAP READING LAMP LENS REMOVAL
(1) Make a straight hook at the end of a large pa-
per clip or wire (approximately 1.5-mm/0.06-in diam-
eter).
(2) Insert the wire hook into the hole in the lamp
lens and pull downward to detach the lens from the
lamp housing (Fig. 4).
MAP READING LAMP LENS INSTALLATION
(1) Insert the tab at the front of the lamp lens into
the slot in the lamp housingÐshown by arrow 1 in
Figure 5.
(2) Force the rear of the lens upward until it is
seated in the lamp housingÐshown by arrow 2 in
Figure 5.
ILLUMINATED ENTRY SYSTEM SERVICE
INFORMATION
The Illuminated Entry System that is activated by
the system relay (TAN). The relay is located on a
bracket (with 3 relays) behind the instrument panel.
The relay receives input from the door pillar
Fig. 2 Dome Lamp Removal/InstallationÐXJ
Vehicles
Fig. 3 Hardtop Dome/Cargo LampÐYJ Vehicles
8L - 20 LAMPSJ

switches, the keyless entry system, and the ignition
switch (when in the RUN position). When correct in-
put is received, the entry module timer immediately
begins the timing-out process. The timing-out process
requires approximately 3066 seconds.
The illuminated entry system also operates
when a door is opened to exit the vehicle. When
the door is closed the interior illumination will
continue for the remaining portion of the 30 sec-
onds.
ILLUMINATED ENTRY SYSTEM TROUBLE
DIAGNOSIS
The Illuminated Entry System relay is located on a
bracket behind the instrument panel.
(1) Ensure that the ignition switch is in the Off po-
sition.
(2) Open and immediately close the driver-side
door. The interior courtesy lamps should immediately
illuminate.
(3) Open driver-side door, enter the vehicle, close
the door and turn the ignition switch to the RUN po-sition. The courtesy lamps should go out. Turn the
ignition switch to the OFF position before exiting ve-
hicle.
(4) When exiting the vehicle, the courtesy lamps
should remain illuminated after the door is closed.
(5) From outside the vehicle, open and close the
passenger-side door. The courtesy lamps should illu-
minate.
RELAY BENCH TEST
(1) Attach a ``jumper'' wire to pin 1. Momentarily
connect pin 1 (battery negative terminal/ground) to
pin 4. The test bulb should light for 3066 seconds,
then go out. If not, replace the relay.
(2) Momentarily connect pin 1 (battery negative
terminal/ground) to pin 4. The test bulb should light.
Attach a ``jumper'' wire to pin 5 and momentarily
connect pin 5 to pin 2. The test bulb should go out. If
not, replace the relay.
(3) Momentarily connect pin 1 (battery negative
terminal/ground) to pin 3. The test bulb should light.
Next, momentarily connect pin 5 to pin 2 (B+) and
the test bulb should go out. If not, replace the relay.
Fig. 4 Map Reading Lamp Lens Removal
Fig. 5 Map Reading Lamp Lens Installation
Fig. 6 Relay Bench Test
JLAMPS 8L - 21

REAR WINDOW DEFOGGER
CONTENTS
page page
GENERAL.............................. 1
XJ .................................... 4YJ .................................... 4
GENERAL
INDEX
page page
Diagnosis............................... 2
Rear Window Defogger Grid Repair........... 2Rear Window Defogger Grid Test............. 1
Switch Testing............................ 2
Using heating elements bonded to the rear window
glass, the rear defogger will clear condensation, frost
and light snow coverings from the rear window.
The horizontal grid lines and vertical bus bar lines,
printed and baked on inside surface of the rear win-
dow glass, comprise an electrical circuit. The electri-
cally conductive lines are composed of a silver-
ceramic material which when baked on glass
becomes bonded to the glass and is highly resistant
to abrasion.
The electrical current required to produce the heat
in the grid is supplied through a relay and driver op-
erated switch. When the switch is momentarily de-
pressed, the relay senses a voltage change. This
voltage change causes the relay to change state and
complete a circuit to energize the relay. Once the re-
lay energizes, the contacts close connecting the grid
to battery power.
On the XJ, the power circuit to the grid is pro-
tected by the 25 amp, #18 fuse in the fuse box.
Power for fuse #18 comes from the power distribu-
tion center, fuse #F10. Power for the relay is pro-
tected by the 20 amp, #8 fuse located in the fuse box.
On the YJ, the grid is protected by a 25 amp #6
fuse, located in the fuse box. Power for the relay is
protected by 15 amp #9 fuse, located in the fuse box.
To defog the rear window, momentarily depress the
rocker switch. A light on the rocker switch will illu-
minate indicating that the defogger is operating.
If the ignition switch is ON the first activation of
the defog/defrost feature will last for 10 minutes.
Succeeding activations will last for 5 minutes unless
the ignition switch is turned OFF; then it will recy-
cle back to 10 minutes for the first activation.To stop defogger operation, momentarily push the
switch a second time.
CAUTION: Use care when washing the inside of the
rear window to prevent damage to the defogger
heating elements. Use a soft cloth and a mild wash-
ing solution. Wiping motions should be parallel to
the heating elements. Also, keep all objects a safe
distance from the window to prevent damaging the
heating elements.
REAR WINDOW DEFOGGER GRID TEST
It is possible, that a break may exist or occur in an
individual grid line resulting in no current flow
through the line. When a grid has an open circuit,
the area of glass normally cleared by that grid re-
mains fogged or iced unless, and until it is cleared by
the adjacent grids.
With the engine running at idle, push the rear
window defogger switch to the ON position and re-
lease. The pilot lamp in the rocker switch should
light, indicating defogger operation.
Using a 12-volt DC voltmeter, contact the positive
lead to the feed side vertical bus element on the in-
side surface of the glass. Contact the negative lead to
the ground side bus element. Meter should read be-
tween 11 and 13 volts. Connect the negative lead of
the voltmeter to a good ground; the meter reading
should be constant.
Keep the negative lead connected to ground. Use
the positive lead and carefully contact each grid at
the approximate centerline of the window.
JREAR WINDOW DEFOGGER 8N - 1

A voltage drop of one-half the full amount, approx-
imately 6 volts, indicates a good grid or closed cir-
cuit.
A voltage drop of 12 volts at the centerline indi-
cates a break in the grid between the positive volt-
meter lead and the ground.
No voltage drop (0 volts) at the centerline indicates
a break in the grid between the centerline and the
voltage source or lead.
The exact location of the break can be pinpointed
by moving positive voltmeter lead to the left or right
along grid. An abrupt change in the voltage reading
will be noticed. The break is at that point in the
grid.
REAR WINDOW DEFOGGER GRID REPAIR
Locate the broken or open grid.
Use the grid repair kit (available as a service part)
by using the following procedure:
(1) Mark the location of the broken or open grid on
the exterior surface of the glass using a suitable
marking pencil.
(2) Lightly rub the area to be repaired (inside the
rear window) using fine steel wool. Clean the area
with alcohol.
(3) Attach two strips of masking tape to the inside
surface of the rear window (above and below the
break in the grid) (Fig. 1).
(4) Remove package separator clamp and mix plas-
tic conductive epoxy thoroughly. Fold in half and cut
center corner to dispense epoxy.
(5) Apply conductive epoxy through slit in mask-
ing tape. Overlap both ends of the break.
(6) For a terminal or pigtail replacement, mask ad-
jacent areas so epoxy can be extended onto line and
buss bar. Apply a thin layer of epoxy to area where
terminal was fastened and to adjacent line.
(7) Apply a thin layer of conductive epoxy on ter-
minal and place terminal on desired location. To pre-
vent terminal from moving while the epoxy is curing,
it must be wedged or clamped.
(8) Carefully remove masking tape from grid line.
(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 from terminal and check out operation
of rear window defogger. Do not attach connectors
until curing is complete.
WARNING: REPAIR KIT MAY CAUSE SKIN OR EYE
IRRITATION.
CONTAINS EPOXY RESIN AND AMINE TYPE
HARDENER, HARMFUL IF SWALLOWED. AVOID
CONTACT WITH SKIN AND EYES. FOR SKIN,
WASH AFFECTED AREAS WITH SOAP AND WA-
TER. DO NOT TAKE INTERNALLY. IF TAKEN
INTERNALLY, INDUCE VOMITING; CALL A
PHYSICIAN IMMEDIATELY. IF IN CONTACT
WITH EYES, FLUSH WITH PLENTY OF WATER.
USE WITH ADEQUATE VENTILATION. DO NOT
USE NEAR FIRE OR FLAME. CONTENTS CON-
TAIN 3% FLAMMABLE SOLVENTS.
WARNING: KEEP OUT OF REACH OF CHIL-
DREN.
SWITCH TESTING
DIAGNOSIS
Refer to Group 8W - Wiring Diagrams for a com-
plete circuit diagram.
BATTERY, IGNITION & FUSES
²Check fuses #6 and #9 (YJ), or #8 and #18 fuse
(XJ). Replace as required.
²If the fuses are not blown check the battery side of
#18 fuse (XJ) or fuse #6 (YJ) for battery voltage. If
battery voltage is not present replace the Maxi fuse
located in the power distribution center.
²Check the ignition side of fuse #9 (YJ), fuse #8
(XJ) for battery voltage. If battery voltage is not
present check for an open from the ignition switch.
DEFOGGER SWITCH
Defogger switch connector separated from de-
fogger switch; turn ignition switch to ON for
voltage tests; turn ignition switch to OFF for re-
sistance tests
²Measure voltage at defogger switch connector ter-
minal D. The meter should read approximately 5
volts momentarily. If not, repair open from relay.
²Refer to switch diagram for resistance tests. If val-
ues do not match, replace defogger switch.
DEFOGGER RELAY
Defogger relay connector separated from de-
fogger relay; turn ignition switch to ON for volt-
age tests; turn ignition switch to OFF for
resistance tests
Fig. 1 Grid Line Repair (Typical)
8N - 2 REAR WINDOW DEFOGGERJ

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