fuse box JEEP CHEROKEE 1995 Service Repair Manual

INTERIOR LAMPS
INDEX
page page
Dome Lamp ReplacementÐXJ............... 17
Dome/Courtesy Lamp Service InformationÐXJ . . . 16
Dome/Courtesy Lamp Trouble DiagnosisÐXJ.... 16Lighted Vanity Mirror Trouble DiagnosisÐXJ..... 16
Lighted Vanity MirrorÐXJ................... 16
Overhead ConsoleÐXJ..................... 17
DOME/COURTESY LAMP SERVICE
INFORMATIONÐXJ
Voltage is applied at all times via the dome lamp
fuse to each of the interior lamp bulbs. The interior
lamp bulbs illuminate when they are connected to
body ground via the switch:
²Headlamp switch.
²Glove box switch.
²Door pillar switch.
²Liftgate switch (if the cargo lamp is ON).
If equipped with Security Alarm Module, refer to
Group 8Q, Vehicle Theft Security System.
DOME/COURTESY LAMP TROUBLE DIAGNOSISÐ
XJ
ALL LAMPS INOPERATIVE
(1) Rotate the headlamp switch rheostat clockwise.
The lamps should light. If not OK, remove, inspect
and test the dome lamp fuse. Replace if bad.
(2) If the fuse is OK, repair the open circuit in the
wire harness to vehicle body ground.
ONE LAMP INOPERATIVE
(1) Measure the resistance across the bulb holder
terminals. The ohmmeter should indicate zero ohms.
If not, replace the bulb.
(2) Measure the voltage between the voltage side
of the bulb holder and vehicle body ground. The volt-
meter should indicate battery voltage. If not, repair
the open circuit in the wire harness to the splice.
LAMPS INOPERATIVE WITH ONE OR MORE
DOORS OPENED
(1) Remove the inoperative switch from the door
pillar and connect the switch wire directly to ground.
The lamp should light.
(2) If not, check for an open circuit in black
(ground) wire. Repair as necessary. If lamps still do
not light, replace the switch.
LIGHTED VANITY MIRRORÐXJ
SERVICE INFORMATION
Both the driver and the front passenger sunvisor
can be equipped with a lighted vanity mirror. A lamplocated at each side of the vanity mirror. The lamps
are switched ON automatically when the mirror
cover is lifted (Fig. 1).
Voltage is applied directly to the vanity lamp bulbs
via the dome lamp fuse.
LIGHTED VANITY MIRROR TROUBLE
DIAGNOSISÐXJ
VANITY LAMPS INOPERATIVE
(1) Remove, inspect and test the dome lamp fuse.
Replace if defective.
(2) Test the dome lamp operation. If OK, go to the
next step. If not OK, repair the open circuit in the
wire harness from the splice.
(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.
Fig. 1 Lighted Vanity Mirror
8L - 16 LAMPSÐXJ VEHICLESJ

POWER SEATS
CONTENTS
page page
DIAGNOSIS............................. 2
GENERAL INFORMATION.................. 1SERVICE PROCEDURES................... 3
GENERAL INFORMATION
A six-way driver's side power seat is an available
option on XJ (Cherokee) models. The power seat sys-
tem receives battery feed through fuse 6 in the power
distribution center and circuit breaker 16 in the fuse-
block module at all times.
Following are general descriptions of the major
components in the power seat system. Refer to Group
8W - Wiring Diagrams for complete circuit descrip-
tions and diagrams.
POWER SEAT SWITCH
The power seat can be adjusted in six different
ways using the power seat switch (Fig. 1). The switch
is located on the lower outboard side of the seat
cushion. Refer to the owner's manual for more infor-
mation on power seat switch functions and seat ad-
justing procedures. The individual switches cannot be
repaired. If one switch fails, the entire switch module
must be replaced.
POWER SEAT ADJUSTER/MOTORS
There are three reversible motors that operate the
power seat adjuster. The motors are connected to
worm-drive gearboxes in the adjuster by drive cables.
The front and rear of a seat are operated by differ-
ent motors. They can be raised or lowered indepen-
dently of each other. When the center seat switch is
pushed to the UP or DOWN position, both front and
rear motors operate in unison, moving the entire seat
up or down. The forward-rearward motor is operated
by pushing the center seat switch to the FORWARD
or REARWARD position.
When a switch is actuated, battery feed and a
ground path are applied through the switch contacts
to the motor(s). The motor(s) operate to move the
seat in the selected direction until the switch is re-
leased, or until the travel limit of the power seat ad-juster is reached. When the switch is moved in the
opposite direction, the battery feed and ground path
to the motor(s) are reversed through the switch con-
tacts. This causes the motor to run in the opposite di-
rection.
Each motor contains a self-resetting circuit breaker
to protect it from overload. Consecutive or frequent
resetting must not be allowed to continue or the mo-
tors may be damaged. Make the necessary repairs.
The power seat adjuster and motors can not be re-
paired, and are serviced only as a complete unit. If
any component in this unit should fail, the entire as-
sembly must be replaced.
Fig. 1 Power Seat Switch
JPOWER SEATS 8R - 1

INTERIOR LIGHTING
INDEX
page page
Cargo Lamp, Courtesy Lamps and Dome Lamp.... 1
Chime/Buzzer Module....................... 2
Diagram Index............................ 2
General Information........................ 1
Glove Box Lamp........................... 1
Ignition Switch Lamp........................ 1Instrument Panel Illumination Lamps............ 1
Reading Lamps........................... 2
Time Delay Relay.......................... 1
Underhood Lamp.......................... 2
Visor Vanity Mirror Lamps.................... 2
GENERAL INFORMATION
Circuit M1 supplies power to the glove box lamp,
left courtesy lamp, right courtesy lamp, dome lamp,
and cargo lamp. The M1 circuit also connects to the
remote keyless entry module. Circuit M1 is protected
by the ignition off draw (IOD) fuse (fuse 9) in the fuse
block.
Circuit E2 supplies power for the instrument panel
illumination lamps.
INSTRUMENT PANEL ILLUMINATION LAMPS
Circuit E2 from the headlamp switch splices to
supply power to the following illumination lamps:
²Ash receiver lamp
²Cigar lighter lamp
²Transmission range indicator lamp
²Transfer case range indicator lamp
²A/C-Heater switch lamp
²Heated rear window lamp
²Rear wiper switch lamp
²Fog lamp switch lamp
Fuse 19 in the fuse block protects circuit E2. Circuit
Z1 provides ground for all of the illumination lamps
except for the cigar lighter lamp. The cigar lighter
lamp is case grounded.
HELPFUL INFORMATION
Circuit E2 also supplies power to the radio, LCD
relay and the illumination lamps in the instrument
cluster.
IGNITION SWITCH LAMP
The time delay relay is used to allow a time-ON
function for the ignition switch lamp and the courtesy
lamp. Power for the relay is received on the M1
circuit from the IOD fuse (fuse F9) in the fuse block.
Circuit M2 provides ground for the time delay relay
through the right and left door ajar switches and the
headlamp switch. When a door is opened, or the
headlamp switch is moved to the dome lamp position,a ground path is provided for the relay on circuit M2.
This energizes the relay, causing the contacts to close.
When the relay contacts close, power is provided
through the relay to circuit M50. The M50 circuit
supplies current to the ignition switch lamp. Circuit
Z1 provides ground for the lamp.
GLOVE BOX LAMP
Circuit M1 from the IOD fuse (fuse F9) in the fuse
block powers the glove box lamp. A case grounded
switch, in series after the lamp, closes when the glove
box door is opened. The switch completes a path to
ground on circuit Z1.
CARGO LAMP, COURTESY LAMPS AND DOME
LAMP
Circuit M1 from the IOD fuse (fuse F9) in the fuse
block supplies power to the cargo, courtesy lamps and
dome lamp. This circuit is HOT at all times. The
ground path for the lamp is provided in three differ-
ent ways.
One way is through the door jamb switches. Circuit
M2 connects to the door jamb switches from the cour-
tesy and dome lamps. The switches are connected to
ground circuit Z1. When a door is opened, the plunger
in the switch closes, completing a path to ground.
The second way is through the liftgate switch. Cir-
cuit M2 connects to circuit M4 at the cargo lamp.
Circuit M4 connects to the liftgate switch. The lift-
gate switch connects to ground circuit Z1. When the
lift gate opens, the plunger in the switch closes, com-
pleting a path to ground.
The third ground path is through the headlamp
switch. Circuit M2 is spliced in with the headlamp
switch. When the operator turns the headlamp switch
to the dome lamp ON position, a ground path is
provided through the switch.
J8W-44 INTERIOR LIGHTINGÐXJ VEHICLES 8W - 44 - 1

READING LAMPS
Circuit M1 from the IOD fuse (fuse F9) in the fuse
block supplies power to the reading lamps. Circuit
M1 is HOT at all times. When the operator depresses
the reading lamp, the reading lamp switch closes and
supplies ground on circuit Z1.
VISOR VANITY MIRROR LAMPS
Circuit M1 from the IOD fuse (fuse F9) in the fuse
block supplies power to the vanity lamps. Circuit M1
is HOT at all times. When the vanity lamps switch
closes, voltage flows to vanity mirror lamps. The van-
ity mirror is case grounded.
UNDERHOOD LAMP
Circuit A6 from fuse 16 in the Power Distribution
Center (PDC) supplies battery voltage for the under-
hood lamp. A mercury switch, in series after the
lamp, connects the lamp to ground on circuit Z1.
When the hood is raised, mercury inside the switch
moves to a position where it connects circuit M1 to
ground circuit Z1, illuminating the lamp.
CHIME/BUZZER MODULE
The buzzer or optional chime module sounds an au-
dible warning tone. The tone sounds for seat belt
warning and when the ignition key is in the ignition
switch while the drivers door is open. The tone also
sounds when the ignition key is in the ON position
while the drivers side seat belt is not buckled. Lastly,
the tone sounds when the headlamps are ON when
the ignition is OFF. Refer to Group 8U for system op-
eration.
When the ignition switch is in the RUN or START
position, circuit F87 from fuse 17 in the fuse block
supplies power to the chime/buzzer module. Circuit
A21 from the ignition switch supplies power to fuse
17.
Circuit L7 from fuse 15 in the fuse block also sup-
plies power to the chime/buzzer module. Circuit A3
from fuse 5 in the Power Distribution Center (PDC)
powers fuse 15.
When the parking lamps or headlamps are ON, the
headlamp switch connects circuit G26 with the driv-
ers side door jamb switch. Circuit G26 also connects
to the key-in switch. Circuit M11 connects the key-in
switch to the chime/buzzer module and the headlamp
switch.
If the headlamps are ON, and the drivers door
opens, ground for the chime/buzzer is on circuit C26
from the headlamp switch through the door jamb
switch to circuit Z1.
If the headlamps are OFF with the key in the ig-
nition while the drivers side door is open, ground forthe chime/buzzer is supplied through the key-in
switch. The ground path is over circuit M11, through
the closed key-in switch to circuit C26. From circuit
C26, the ground path continues through the drivers
door jamb switch to circuit Z1.
Circuit G11 from the buzzer powers the seat belt
warning lamp in the instrument cluster. Circuit Z1
at the instrument cluster provides ground for the
lamp.
Circuit G10 from the buzzer connects to the seat
belt switch. When the seat belt switch closes a path
to ground is completed on circuit Z1 and the tone
sounds momentarily.
Circuit Z1 also grounds the chime\buzzer module.
HELPFUL INFORMATION
Circuit F87 also powers the instrument cluster and
the headlamp delay module.
DIAGRAM INDEX
Component Page
Cargo Lamp............................8W-44-6
Chime/Buzzer Module......................8W-44-3
Courtesy Lamps.........................8W-44-5
Dome Lamp............................8W-44-7
Door Jamb Switches.....................8W-44-10
Fuse 3 (PDC).........................8W-44-4, 6
Fuse 5 (PDC).........................8W-44-3, 8
Fuse 6 (PDC)...........................8W-44-3
Fuse 9 (Fuse Block).....................8W-44-4, 6
Fuse 15 (Fuse Block)....................8W-44-3, 8
Fuse 16 (PDC)........................8W-44-4, 6
Fuse 17 (Fuse Block)......................8W-44-3
Fuse 19 (Fuse Block)......................8W-44-8
Glove Box Lamp and Switch.................8W-44-5
Headlamp Switch...................8W-44-3, 4, 5, 8
Headlamp Delay Module....................8W-44-4
Headlamp Delay Relay.....................8W-44-3
Ignition Switch..........................8W-44-3
Instrument Cluster........................8W-44-3
Instrument Panel Illumination Lamps..........8W-44-8, 9
Intermittent Wiper Control Module.............8W-44-4
Key-In Switch...........................8W-44-4
Liftgate Switch..........................8W-44-6
Reading Lamps..........................8W-44-7
Remote Keyless Entry Module................8W-44-7
Seat Belt Switch.........................8W-44-3
Telltale Connector (Instrument Cluster)...........8W-44-3
Time Delay Relay........................8W-44-4
Underhood Lamp.........................8W-44-4
Vanity Lamps...........................8W-44-7
8W - 44 - 2 8W-44 INTERIOR LIGHTINGÐXJ VEHICLESJ

INTERIOR LIGHTING
INDEX
page page
Cargo Lamp and Dome Lamp................. 1
Chime/Buzzer Module....................... 2
Diagram Index............................ 2
General Information........................ 1
Glove Box Lamp........................... 1Ignition Switch Lamp........................ 1
Instrument Panel Illumination Lamps............ 1
Reading Lamps........................... 1
Underhood Lamp.......................... 1
Visor Vanity Mirror Lamps.................... 1
GENERAL INFORMATION
Circuit M1 supplies power to the glove box lamp,
dome lamp, reading lamps, cargo lamp and vanity
lamps. Circuit M1 is protected by fuse 16 in the
Power Distribution Center (PDC).
Circuit E2 supplies power for the instrument panel
illumination lamps.
INSTRUMENT PANEL ILLUMINATION LAMPS
Circuit E2 from the headlamp switch splices to
supply power to the following illumination lamps:
²Ash receiver lamp
²Cigar lighter lamp
²Transmission range indicator lamp
²Transfer case range indicator lamp
²A/C-Heater switch lamp
²Heated rear window switch lamp
²Rear wiper switch lamp
²Fog lamp switch lamp
Fuse 25 in the fuse block protects circuit E2. Cir-
cuit Z1 provides ground for all of the illumination
lamps except for the cigar lighter lamp. The cigar
lighter lamp is case grounded.
HELPFUL INFORMATION
Circuit E2 also supplies power to the radio, LCD
relay and the illumination lamps in the instrument
cluster.
IGNITION SWITCH LAMP
Circuit M50 supplies voltage to the ignition switch
lamp. Circuit Z1 provides ground for the lamp.
GLOVE BOX LAMP
Circuit M1 from fuse 16 in the Power Distribution
Center (PDC) powers the glove box lamp. A case
grounded switch, in series after the lamp, closes
when the glove box door is opened. The switch com-
pletes a path to ground on circuit Z1.
CARGO LAMP AND DOME LAMP
Circuit M1 from fuse 16 in the Power Distribution
Center (PDC) supplies power to the cargo lamp anddome lamp. The M1 circuit is HOT at all times. The
ground path for the lamp is provided in three differ-
ent ways.
One way is through the door jamb switches. Circuit
M2 connects to the door jamb switches to the dome
lamp and cargo lamp. The switches are connected to
ground circuit Z1. When a door is opened, the
plunger in the switch closes, completing a path to
ground.
The second way is through the liftgate switch. Cir-
cuit G71 connects to circuit M2 at the cargo lamp
connector. Circuit G71 connects to the liftgate switch.
The liftgate switch connects to ground circuit Z1.
When the lift gate opens, the plunger in the switch
closes, completing a path to ground.
The third ground path is through the headlamp
switch. Circuit M2 is spliced in with the headlamp
switch. When the operator turns the headlamp
switch to the dome lamp ON position, a ground path
is provided through the switch.
READING LAMPS
Circuit M1 from fuse 16 in the Power Distribution
Center (PDC) supplies power to the reading lamps.
Circuit M1 is HOT at all times. When the operator
depresses the reading lamp, the reading lamp switch
closes and supplies ground on circuit Z1.
VISOR VANITY MIRROR LAMPS
Circuit M1 from fuse 16 in the Power Distribution
Center (PDC) supplies power to the vanity lamps.
Circuit M1 is HOT at all times. When the vanity
lamps switch closes, voltage flows to vanity mirror
lamps. The vanity mirror is case grounded.
UNDERHOOD LAMP
Circuit A7 from fuse 16 in the Power Distribution
Center (PDC) supplies battery voltage for the under-
hood lamp. A mercury switch, in series after the
lamp, connects the lamp to ground on circuit Z1.
When the hood is raised, mercury inside the switch
moves to a position where it connects circuit M1 to
ground circuit Z1, illuminating the lamp.
J8W-44 INTERIOR LIGHTINGÐXJ-RHD 8W - 44 - 1

CHIME/BUZZER MODULE
The buzzer or optional chime module sounds an au-
dible warning tone. The tone sounds for seat belt
warning and when the ignition key is in the ignition
switch while the drivers door is open. The tone also
sounds when the ignition key is in the ON position
while the drivers side seat belt is not buckled. Lastly,
the tone sounds when the headlamps are ON when
the ignition is OFF. Refer to Group 8U for system op-
eration.
When the ignition switch is in the RUN or START
position, fuse F87 from fuse 26 in the fuse block sup-
plies power to the chime/buzzer module. Circuit A21
from the ignition switch supplies power to fuse 26.
Circuit L7 from fuse 9 in the fuse block also sup-
plies power to the chime/buzzer module. Circuit A3
from fuse 5 in the Power Distribution Center (PDC)
powers fuse 9.
When the parking lamps or headlamps are ON, the
headlamp switch connects circuit G26 with the driv-
ers side door jamb switch. Circuit G26 also connects
to the key-in switch. Circuit M11 connects the key-in
switch to the chime module and the headlamp
switch.
If the headlamps are ON, and the drivers door
opens, ground for the chime/buzzer is on circuit C26
from the headlamp switch through the door jamb
switch to circuit Z1.
If the headlamps are OFF with the key in the ig-
nition while the drivers side door is open, ground for
the chime/buzzer is supplied through the key-in
switch. The ground path is over circuit M11, through
the closed key-in switch to circuit C26. From circuit
C26, the ground path continues through the drivers
door jamb switch to circuit Z1.
Circuit G11 from the buzzer powers the seat belt
warning lamp in the instrument cluster. Circuit Z1
at the instrument cluster provides ground for the
lamp.Circuit G10 from the buzzer connects to the seat
belt switch. When the seat belt switch closes a path
to ground is completed on circuit Z1 and the tone
sounds momentarily.
Circuit Z1 also grounds the chime buzzer module.
HELPFUL INFORMATION
Circuit F87 also powers the instrument cluster and
the headlamp delay module.
DIAGRAM INDEX
Component Page
Cargo Lamp............................8W-44-6
Chime/Buzzer Module......................8W-44-3
Courtesy Lamps.........................8W-44-5
Dome Lamp............................8W-44-6
Door Jamb Switches......................8W-44-7
Fuse 3 (PDC)...........................8W-44-6
Fuse 5 (PDC).........................8W-44-5, 8
Fuse 6 (PDC)...........................8W-44-6
Fuse 9 (Fuse Block).....................8W-44-3, 8
Fuse 16 (PDC)........................8W-44-4, 6
Fuse 25 (Fuse Block)......................8W-44-8
Fuse 26 (Fuse Block)......................8W-44-3
Glove Box Lamp and Switch.................8W-44-5
Headlamp Switch....................8W-44-3, thru 8
Headlamp Delay Module....................8W-44-3
Ignition Switch..........................8W-44-3
Instrument Cluster......................8W-44-3, 9
Instrument Panel Illumination Lamps..........8W-44-8, 9
Key-In Switch...........................8W-44-4
Liftgate Switch..........................8W-44-6
Reading Lamps..........................8W-44-6
Seat Belt Switch.........................8W-44-3
Telltale Connector (Instrument Cluster)...........8W-44-3
Time Delay Relay........................8W-44-4
Underhood Lamp.........................8W-44-4
8W - 44 - 2 8W-44 INTERIOR LIGHTINGÐXJ-RHDJ

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

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