2002 JEEP LIBERTY Power distribution unit

the engine compartment, on the front extension of
the right front wheel house panel below and behind
the right headlamp. This unit is designed to provide
the audible alert requirements for the ROW premium
VTA.
The alarm siren module consists of microprocessor-
based electronic control circuitry, the siren, and a
nickel metal hydride backup battery. All of the alarm
module components are protected and sealed within
a black molded plastic housing. A stamped steel
mounting bracket is secured to the module with
three stud plates and nuts that fit into slotted holes
at the top and each side of the bracket. The front
surface of the bracket features a tightly grouped
series of small holes that serves as an outlet for the
audible output of the alarm siren. The bottom of the
mounting bracket is bent at a right angle and has an
integral locating tab feature. Two mounting holes in
the horizontal surface of the bracket are used to
secure the alarm siren module to the wheel house
extension with two screws. An integral connector
receptacle extends forward from the upper left corner
of the alarm siren housing, and connects the unit to
the vehicle electrical system through a dedicated
take out and connector of the headlamp and dash
wire harness.
The alarm siren module cannot be repaired or
adjusted and, if faulty or damaged, it must be
replaced.
OPERATION
The microprocessor within the alarm siren module
performs the tasks required to provide the siren unit
features and functions based upon internal program-
ming and electronic arm and disarm message inputs
received from the Intrusion Transceiver Module
(ITM) over a dedicated serial bus communication cir-
cuit. The alarm siren module will self-detect prob-
lems with its internal and external power supply and
communication circuits, then send electronic mes-
sages indicating the problem to the ITM upon receiv-
ing a request from the ITM. The ITM will store a
Diagnostic Trouble Code (DTC) for a detected alarm
siren module fault that can be retrieved with the
DRBIIItscan tool over the Programmable Communi-
cations Interface (PCI) data bus network through the
16-way data link connector located on the driver side
lower edge of the instrument panel.
When the Rest-Of-World (ROW) premium version
of the Vehicle Theft Alarm (VTA) is armed, the alarm
siren module microprocessor continuously monitors
inputs from the ITM for messages to sound its inter-
nal siren and enters its auto-detect mode. While in
the auto-detect mode, if the alarm siren module
detects that its power supply or communication cir-
cuits are being tampered with or have been sabo-taged, it will sound an alarm and continue to operate
through its on-board backup battery. If the arm siren
module is in its disarmed mode when its power sup-
ply or communication circuits are interrupted, the
siren will not sound. The alarm module will also
notify the ITM when the backup battery requires
charging, and the ITM will send a message that will
allow the backup battery to be charged through the
battery current and ground circuits to the alarm
module only when the ignition switch is in the On
position and the engine is running. This will prevent
the charging of the alarm backup battery from
depleting the charge in the main vehicle battery
while the vehicle is not being operated.
The alarm siren module receives battery current
on a fused B(+) circuit through a fuse in the Power
Distribution Center (PDC), and receives ground
through a ground circuit and take out of the head-
lamp and dash wire harness. This ground take out
has a single eyelet terminal connector that is secured
by a ground screw to the left inner fender shield in
the engine compartment. These connections allow the
alarm siren module to remain operational, regardless
of the ignition switch position. The hard wired inputs
and outputs for the alarm siren module may be diag-
nosed and tested using conventional diagnostic tools
and procedures. However, conventional diagnostic
methods will not prove conclusive in the diagnosis of
the internal circuitry or the backup battery of the
alarm siren module, the ITM, the serial bus commu-
nication line, or the electronic message inputs to and
outputs from the alarm siren module. The most reli-
able, efficient, and accurate means to diagnose the
alarm siren module, the ITM, the serial bus commu-
nication line, and the electronic message inputs to
and outputs from the alarm siren module requires
the use of a DRBIIItscan tool. Refer to the appro-
priate diagnostic information.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Disconnect the headlamp and dash wire har-
ness connector for the alarm siren module from the
module connector receptacle (Fig. 14).
(3) Remove the two screws that secure the alarm
siren module to the front extension of the right front
wheel house panel.
(4) Remove the alarm siren module from the front
extension of the right front wheel house panel.
INSTALLATION
(1) Position the alarm siren module onto the front
extension of the right front wheel house panel (Fig.
14).
KJVEHICLE THEFT SECURITY 8Q - 17
SIREN (Continued)

An electrically operated intermittent front wiper
and washer system is standard factory-installed
safety equipment on this model (Fig. 1). The front
wiper and washer system includes the following
major components, which are described in further
detail elsewhere in this service information:
²Body Control Module- The Body Control
Module (BCM) is located on the Junction Block (JB)
under the driver side outboard end of the instrument
panel. (Refer to 8 - ELECTRICAL/ELECTRONIC
CONTROL MODULES/BODY CONTROL MODULE
- DESCRIPTION).
²Front Check Valve- The front washer system
check valve is integral to the wye fitting located in
the washer plumbing between the cowl plenum
washer hose and the front washer nozzles, and is
concealed beneath the cowl plenum cover/grille panel
at the base of the windshield.
²Front Washer Nozzle- Two fluidic front
washer nozzles are secured with integral snap fea-
tures to dedicated openings in the cowl plenum cover/
grille panel located near the base of the windshield.
²Front Washer Plumbing- The plumbing for
the front washer system consists of rubber hoses and
molded plastic fittings. The plumbing is routed along
the right side of the engine compartment from the
washer reservoir, and through the dash panel into
the cowl plenum to the front washer nozzle fittings
beneath the cowl plenum cover/grille panel.
²Front Wiper Arm- The two front wiper arms
are secured with nuts to the threaded studs on the
ends of the two wiper pivot shafts, which extend
through the cowl plenum cover/grille panel located
near the base of the windshield.
²Front Wiper Blade- The two front wiper
blades are secured to the two front wiper arms with
an integral latch, and are parked on the glass near
the bottom of the windshield when the front wiper
system is not in operation.
²Front Wiper Module- The front wiper pivot
shafts are the only visible components of the front
wiper module. The remainder of the module is con-
cealed within the cowl plenum area beneath the cowl
plenum cover/grille panel. The front wiper module
includes the wiper module bracket, four rubber-iso-
lated wiper module mounts, the front wiper motor,
the wiper motor crank arm, the two wiper drive
links, and the two front wiper pivots.
²Multi-Function Switch- The multi-function
switch is located on the top of the steering column,
just below the steering wheel. The multi-function
switch includes a left (lighting) control stalk and a
right (wiper) control stalk. The right control stalk is
dedicated to providing all of the driver controls for
both the front and rear wiper systems. (Refer to 8 -ELECTRICAL/LAMPS/LIGHTING - EXTERIOR/
MULTI-FUNCTION SWITCH - DESCRIPTION).
²Washer Fluid Level Switch- The washer fluid
level switch is located in a dedicated hole near the
center of the rearward facing surface of the washer
reservoir, behind the right front wheel house splash
shield.
²Washer Pump/Motor- The reversible electric
washer pump/motor unit is located in a dedicated
hole on the lower outboard side of the washer reser-
voir, behind the right front wheel house splash
shield. This single reversible washer pump/motor
provides washer fluid to either the front or rear
washer system plumbing, depending upon the direc-
tion of the pump motor rotation.
²Washer Reservoir- The washer reservoir is
concealed behind the right front wheel house splash
shield ahead of the right front wheel. The washer
reservoir filler neck is the only visible portion of the
reservoir, and it is accessed from the right front cor-
ner of the engine compartment.
²Wiper High-Low Relay- The wiper high-low
relay is an International Standards Organization
(ISO) micro relay located in the Power Distribution
Center (PDC) in the engine compartment near the
battery.
²Wiper On-Off Relay- The wiper on-off relay is
an International Standards Organization (ISO) micro
relay located in the Power Distribution Center (PDC)
in the engine compartment near the battery.
Hard wired circuitry connects the front wiper and
washer system components to the electrical system of
the vehicle. These hard wired circuits are integral to
several wire harnesses, which are routed throughout
the vehicle and retained by many different methods.
These circuits may be connected to each other, to the
vehicle electrical system and to the front wiper and
washer system components through the use of a com-
bination of soldered splices, splice block connectors,
and many different types of wire harness terminal
connectors and insulators. Refer to the appropriate
wiring information. The wiring information includes
wiring diagrams, proper wire and connector repair
procedures, further details on wire harness routing
and retention, as well as pin-out and location views
for the various wire harness connectors, splices and
grounds.
OPERATING MODES The components of the front
wiper and washer system are designed to work in
concert to provide the following operating modes:
²Continuous Wipe Mode- The control knob on
the right (wiper) control stalk of the multi-function
switch has two continuous wipe positions, Low and
High. When selected, these switch positions will
cause the two-speed front wiper motor to operate in a
continuous low or high speed cycle.
KJFRONT WIPERS/WASHERS 8R - 3
FRONT WIPERS/WASHERS (Continued)

²Intermittent Wipe Mode- The control knob on
the right (wiper) control stalk of the multi-function
switch has five minor detent intermittent wipe posi-
tions. When selected, these switch positions will
cause the front wiper system to operate with one of
five delay intervals between complete wipe cycles.
²Mist Wipe Mode- The right (wiper) control
stalk of the multi-function switch has a momentary
Mist position. When selected, this switch position
will operate the front wipers in a low speed continu-
ous cycle for as long as the switch is held closed,
then will complete the current wipe cycle and park
the front wiper blades near the base of the wind-
shield when the switch is released.
²Washer Mode- When the momentary front
wash position of the right (wiper) control stalk of the
multi-function switch is selected with the front wiper
system operating in a continuous wipe mode, washer
fluid will be dispensed onto the windshield glass
through the washer nozzles for as long as the washer
switch is held closed. When the front washer switch
is actuated with the front wiper system operating in
an intermittent wipe mode, washer fluid is still dis-
pensed until the switch is released; however, the
front wipers will operate in a low speed continuous
cycle from the time the washer switch is closed until
several wipe cycles after the switch is released,
before returning to the selected intermittent wipe
mode.
²Wipe-After-Wash Mode- When the momentary
front wash position of the right (wiper) control stalk
of the multi-function switch is selected with the front
wiper system turned Off, the internal circuitry of the
BCM provides a wipe-after-wash feature. When
selected, this feature will operate the washer pump/
motor and the front wipers for as long as the front
washer switch is held closed, then provide several
additional wipe cycles after the switch is released
before parking the front wiper blades near the base
of the windshield.
OPERATION
The front wiper and washer system is designed to
provide the vehicle operator with a convenient, safe,
and reliable means of maintaining visibility through
the windshield glass. The various components of this
system are designed to convert electrical energy pro-
duced by the vehicle electrical system into the
mechanical action of the wiper blades to wipe the
outside surface of the glass, as well as into the
hydraulic action of the washer system to apply
washer fluid stored in an on-board reservoir to the
area of the glass to be wiped. When combined, these
components provide the means to effectively main-
tain clear visibility for the vehicle operator by remov-
ing excess accumulations of rain, snow, bugs, mud, orother minor debris from the outside windshield glass
surface that might be encountered while driving the
vehicle under numerous types of inclement operating
conditions.
The vehicle operator initiates all front wiper and
washer system functions with the right (wiper) con-
trol stalk of the multi-function switch that extends
from the right side of the steering column, just below
the steering wheel. Rotating the control knob on the
end of the control stalk, selects the Off, Delay, Low,
or High front wiper system operating modes. In the
Delay mode, the control knob also allows the vehicle
operator to select from one of five intermittent wipe
Delay intervals. Pulling the right control stalk down-
wards actuates the momentary front wiper system
Mist mode switch, while pulling the right control
stalk towards the steering wheel actuates the
momentary front washer system switch. The multi-
function switch provides hard wired resistor multi-
plexed inputs to the Body Control Module (BCM) for
all of the front wiper system functions, as well as a
separate hard wired sense input to the BCM for the
front washer system function.
The front wiper and washer system will only oper-
ate when the ignition switch is in the Accessory or
On positions. Battery current is directed from a B(+)
fuse in the Power Distribution Center (PDC) to the
wiper and washer system circuit breaker in the Junc-
tion Block (JB) through a fused ignition switch out-
put (run-acc) circuit. The automatic resetting circuit
breaker then provides battery current through a
fused ignition switch output (run-acc) circuit to the
wiper high/low relay, the wiper on/off relay, and the
park switch within the front wiper motor. A separate
fuse in the JB provides battery current through
another fused ignition switch output (run-acc) circuit
to the multi-function switch. The multi-function
switch circuitry uses this battery feed and a ground
circuit input to directly control the operation and
direction of the reversible electric washer pump/mo-
tor unit. The BCM uses low side drivers to control
front wiper system operation by energizing or de-en-
ergizing the wiper high/low and wiper on/off relays.
The hard wired circuits and components of the
front wiper and washer system may be diagnosed
and tested using conventional diagnostic tools and
procedures. However, conventional diagnostic meth-
ods may not prove conclusive in the diagnosis of the
Body Control Module (BCM), or the inputs to or out-
puts from the BCM that control the front wiper and
washer system operating modes. The most reliable,
efficient, and accurate means to diagnose the BCM,
or the BCM inputs and outputs related to the various
front wiper and washer system operating modes
requires the use of a DRBIIItscan tool. Refer to the
appropriate diagnostic information.
8R - 4 FRONT WIPERS/WASHERSKJ
FRONT WIPERS/WASHERS (Continued)

of the washer pump/motor unit is connected to the
front nipple.
(10) Engage the ªWº clip that secures the front
bumper fascia to the front bumper support. This clip
is located behind the bumper support and below the
right front lamp unit.
(11) Reinstall the splash shield into the right front
fender wheel house. (Refer to 23 - BODY/EXTERIOR/
WHEELHOUSE SPLASH SHIELD - INSTALLA-
TION).
(12) Lower the vehicle.
(13) Install and tighten the screw that secures the
washer reservoir filler neck support to upper radiator
crossmember (Fig. 23). Tighten the screw to 7 N´m
(65 in. lbs.).
(14) Reinstall the air cleaner housing onto the top
of the right front fender wheel house. (Refer to 9 -
ENGINE/AIR INTAKE SYSTEM/AIR CLEANER
ELEMENT - INSTALLATION).
(15) Refill the washer reservoir with the washer
fluid drained from the reservoir during the removal
procedure.
(16) Reconnect the battery negative cable.
WIPER HIGH/LOW RELAY
DESCRIPTION
The wiper high/low relay is located in the Power
Distribution Center (PDC) in the engine compart-
ment near the battery. The wiper high/low relay is a
conventional International Standards Organization
(ISO) micro relay (Fig. 25). Relays conforming to theISO specifications have common physical dimensions,
current capacities, terminal patterns, and terminal
functions. The relay is contained within a small, rect-
angular, molded plastic housing and is connected to
all of the required inputs and outputs by five integral
male spade-type terminals that extend from the bot-
tom of the relay base.
The wiper high/low relay cannot be adjusted or
repaired and, if faulty or damaged, the unit must be
replaced.
OPERATION
The wiper high/low relay is an electromechanical
switch that uses a low current input from the Body
Control Module (BCM) to control a high current out-
put to the front wiper motor. The movable common
feed contact point is held against the fixed normally
closed contact point by spring pressure. When the
relay coil is energized, an electromagnetic field is
produced by the coil windings. This electromagnetic
field draws the movable relay contact point away
from the fixed normally closed contact point, and
holds it against the fixed normally open contact
point. When the relay coil is de-energized, spring
pressure returns the movable contact point back
against the fixed normally closed contact point. A
resistor is connected in parallel with the relay coil in
the relay, and helps to dissipate voltage spikes and
electromagnetic interference that can be generated as
the electromagnetic field of the relay coil collapses.
The wiper high/low relay terminals are connected
to the vehicle electrical system through a connector
receptacle in the Power Distribution Center (PDC).
The inputs and outputs of the wiper high/low relay
include:
²Common Feed Terminal- The common feed
terminal (30) is connected to the output of the wiper
on/off relay at all times through the wiper on/off
relay output circuit.
²Coil Ground Terminal- The coil ground termi-
nal (85) is connected to a control output of the Body
Control Module (BCM) through a front wiper high/
low relay control circuit. The BCM controls front
wiper motor operation by controlling a ground path
through this circuit.
²Coil Battery Terminal- The coil battery ter-
minal (86) receives battery current at all times from
a circuit breaker in the Junction Block (JB) through
a fused ignition switch output (run-acc) circuit.
²Normally Open Terminal- The normally open
terminal (87) is connected to the high speed brush of
the front wiper motor through a front wiper high/low
relay high speed output circuit, and is connected to
the high speed brush whenever the relay is ener-
gized.
Fig. 25 ISO Micro Relay
30 - COMMON FEED
85 - COIL GROUND
86 - COIL BATTERY
87 - NORMALLY OPEN
87A - NORMALLY CLOSED
KJFRONT WIPERS/WASHERS 8R - 23
WASHER RESERVOIR (Continued)

WIPER ON/OFF RELAY
DESCRIPTION
The wiper on/off relay is located in the Power Dis-
tribution Center (PDC) in the engine compartment
near the battery. The wiper on/off relay is a conven-
tional International Standards Organization (ISO)
micro relay (Fig. 28). Relays conforming to the ISO
specifications have common physical dimensions, cur-
rent capacities, terminal patterns, and terminal func-
tions. The relay is contained within a small,
rectangular, molded plastic housing and is connected
to all of the required inputs and outputs by five inte-
gral male spade-type terminals that extend from the
bottom of the relay base.
The wiper on/off relay cannot be adjusted or
repaired and, if faulty or damaged, the unit must be
replaced.
OPERATION
The wiper on/off relay is an electromechanical
switch that uses a low current input from the Body
Control Module (BCM) to control a high current out-put to the front wiper motor. The movable common
feed contact point is held against the fixed normally
closed contact point by spring pressure. When the
relay coil is energized, an electromagnetic field is
produced by the coil windings. This electromagnetic
field draws the movable relay contact point away
from the fixed normally closed contact point, and
holds it against the fixed normally open contact
point. When the relay coil is de-energized, spring
pressure returns the movable contact point back
against the fixed normally closed contact point. A
resistor is connected in parallel with the relay coil in
the relay, and helps to dissipate voltage spikes and
electromagnetic interference that can be generated as
the electromagnetic field of the relay coil collapses.
The wiper on/off relay terminals are connected to
the vehicle electrical system through a connector
receptacle in the Power Distribution Center (PDC).
The inputs and outputs of the wiper on/off relay
include:
²Common Feed Terminal- The common feed
terminal (30) is connected to the common feed termi-
nal of the wiper high/low relay at all times through
the wiper on/off relay output circuit.
²Coil Ground Terminal- The coil ground termi-
nal (85) is connected to a control output of the Body
Control Module (BCM) through a front wiper on/off
relay control circuit. The BCM controls front wiper
motor operation by controlling a ground path through
this circuit.
²Coil Battery Terminal- The coil battery ter-
minal (86) receives battery current at all times from
a circuit breaker in the Junction Block (JB) through
a fused ignition switch output (run-acc) circuit.
²Normally Open Terminal- The normally open
terminal (87) receives battery current at all times
from a circuit breaker in the Junction Block (JB)
through a fused ignition switch output (run-acc) cir-
cuit, and provides battery current to the front wiper
on/off relay output circuit whenever the relay is ener-
gized.
²Normally Closed Terminal- The normally
closed terminal (87A) is connected to the wiper park
switch in the front wiper motor through the front
wiper park switch sense circuit, and is connected to
the wiper park switch whenever the relay is de-ener-
gized.
The wiper on/off relay can be diagnosed using con-
ventional diagnostic tools and methods.
Fig. 28 ISO Micro Relay
30 - COMMON FEED
85 - COIL GROUND
86 - COIL BATTERY
87 - NORMALLY OPEN
87A - NORMALLY CLOSED
KJFRONT WIPERS/WASHERS 8R - 25

(2) Resistance between terminals 85 and 86 (elec-
tromagnet) should be 67.5 to 82.5 ohms. If OK, go to
Step 3. If not OK, replace the faulty relay.
(3) Connect a battery to terminals 85 and 86.
There should now be continuity between terminals
30 and 87, and no continuity between terminals 87A
and 30. If OK, see Relay Circuit Test. If not OK,
replace the faulty relay.
RELAY CIRCUIT TEST
For circuit descriptions and diagrams, (Refer to
Appropriate Wiring Information).
(1) The relay common feed terminal cavity (30) is
connected to fused battery feed. There should be bat-
tery voltage at the cavity for relay terminal 30 at all
times. If OK, go to Step 2. If not OK, repair the open
circuit to the fuse in the PDC as required.
(2) The relay normally closed terminal (87A) is not
used in this application. Go to Step 3.
(3) The relay normally open terminal cavity (87) is
connected to the compressor clutch coil. There should
be continuity between this cavity and the A/C com-
pressor clutch relay output circuit cavity of the com-
pressor clutch coil wire harness connector. If OK, go
to Step 4. If not OK, repair the open circuit as
required.
(4) The relay coil battery terminal (86) is con-
nected to the fused ignition switch output (run/start)circuit. There should be battery voltage at the cavity
for relay terminal 86 with the ignition switch in the
On position. If OK, go to Step 5. If not OK, repair the
open circuit to the fuse in the junction block as
required.
(5) The coil ground terminal cavity (85) is switched
to ground through the Powertrain Control Module
(PCM). There should be continuity between this cav-
ity and the A/C compressor clutch relay control cir-
cuit cavity of the PCM wire harness connector C
(gray) at all times. If not OK, repair the open circuit
as required.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the cover from the Power Distribution
Center (PDC).
(3) Refer to the label on the PDC for compressor
clutch relay identification and location.
(4) Unplug the compressor clutch relay from the
PDC.
INSTALLATION
(1) Install the compressor clutch relay by aligning
the relay terminals with the cavities in the PDC and
pushing the relay firmly into place.
(2) Install the PDC cover.
(3) Connect the battery negative cable.
(4) Test the relay operation.
A/C HEATER CONTROL
DESCRIPTION
Both the heater-only and A/C heater systems use a
combination of mechanical, electrical, and vacuum
controls. These controls provide the vehicle operator
with a number of setting options to help control the
climate and comfort within the vehicle. Refer to the
owner's manual in the vehicle glove box for more
information on the features, use, and suggested oper-
ation of these controls.
The heater-only or A/C heater control panel is
located to the right of the instrument cluster on the
instrument panel. The control panel contains a rota-
ry-type temperature control knob, a rotary-type mode
control switch knob, and a rotary-type blower motor
speed switch knob. The control also has a push but-
ton to activate the rear window defogger.
The heater-only or A/C heater control panel cannot
be repaired. If faulty or damaged, the entire unit
must be replaced. The illumination lamps are avail-
able for service replacement.
Fig. 10 COMPRESSOR CLUTCH RELAY
30 - COMMON FEED
85 - COIL GROUND
86 - COIL BATTERY
87 - NORMALLY OPEN
87A - NORMALLY CLOSED
24 - 16 CONTROLSKJ
A/C COMPRESSOR CLUTCH RELAY (Continued)

BLOWER MOTOR SWITCH
DESCRIPTION
The heater-only or A/C Heater blower motor is con-
trolled by a four position rotary-type blower motor
switch, mounted in the A/C Heater control panel. The
switch allows the selection of one of four blower
motor speeds, but can only be turned off by selecting
the Off position with the heater-only or A/C Heater
mode control switch knob.
OPERATION
The blower motor switch directs the blower motor
ground path through the mode control switch to the
blower motor resistor, or directly to ground, as
required to achieve the selected blower motor speed.
The blower motor switch cannot be repaired and, if
faulty or damaged, the entire heater-only or A/C
Heater control unit must be replaced.
DIAGNOSIS AND TESTING - BLOWER MOTOR
SWITCH
For circuit descriptions and diagrams, (Refer to
Appropriate Wiring Information).
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN AN ACCIDENTAL
AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Check for battery voltage at the fuse in the
Power Distribution Center (PDC). If OK, go to Step
2. If not OK, repair the shorted circuit or component
as required and replace the faulty fuse.
(2) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Remove the A/C Heater control from the instrument
panel. Check for continuity between the ground cir-
cuit cavity of the A/C Heater control wire harness
connector and a good ground. There should be conti-
nuity. If OK, go to Step 3. If not OK, repair the open
circuit to ground as required.
(3) With the A/C Heater control wire harness con-
nector unplugged, place the A/C Heater mode control
switch knob in any position except the Off position.
Check for continuity between the ground circuit ter-minal and each of the blower motor driver circuit ter-
minals of the A/C Heater control as you move the
blower motor switch knob to each of the four speed
positions. There should be continuity at each driver
circuit terminal in only one blower motor switch
speed position. If OK, test and repair the blower
driver circuits between the A/C Heater control con-
nector and the blower motor resistor as required. If
not OK, replace the faulty A/C Heater control unit.
REMOVAL
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN AN ACCIDENTAL
AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
The blower motor switch cannot be repaired and, if
faulty or damaged, the entire heater-only or A/C
Heater control unit must be replaced. (Refer to 24 -
HEATING & AIR CONDITIONING/CONTROLS/A/C
HEATER CONTROL - REMOVAL)
INSTALLATION
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN AN ACCIDENTAL
AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) The blower motor switch cannot be repaired
and, if faulty or damaged the entire heater-only or
A/C heater control unit must be replaced(Refer to 24
- HEATING & AIR CONDITIONING/CONTROLS/
A/C HEATER CONTROL - INSTALLATION).
KJCONTROLS 24 - 23

BLOWER MOTOR
DESCRIPTION
The blower motor and blower wheel are located in
the passenger side end of the HVAC housing, below
the glove box. The blower motor controls the velocity
of air flowing through the HVAC housing by spinning
a squirrel cage-type blower wheel within the housing
at the selected speed. The blower motor and wheel
can be removed from the housing inside the vehicle
without removing the dash or HVAC housing assem-
bly.
OPERATION
The blower motor will only operate when the igni-
tion switch is in the On position, and the A/C Heater
mode control switch knob is in any position, except
Off. The blower motor receives a fused battery feed
through the blower motor relay whenever the igni-
tion switch is in the On position. The blower motor
battery feed circuit is protected by a fuse in the
Power Distribution Center (PDC). Blower motor
speed is controlled by regulating the ground path
through the A/C Heater control blower motor switch
and the blower motor resistor.
The blower motor and blower motor wheel cannot
be repaired and, if faulty or damaged, they must be
replaced. The blower motor and blower wheel are ser-
viced only as a unit.
DIAGNOSIS AND TESTING - BLOWER MOTOR
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN AN ACCIDENTAL
AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
For circuit descriptions and diagrams, (Refer to
Appropriate Wiring Information). Possible causes of
an inoperative blower motor include:²Faulty fuse
²Faulty blower motor circuit wiring or wire har-
ness connectors
²Faulty blower motor resistor
²Faulty blower motor relay
²Faulty blower motor switch
²Faulty A/C Heater mode control switch
²Faulty blower motor.
Possible causes of the blower motor not operating
in all speeds include:
²Faulty blower motor switch
²Faulty blower motor resistor
²Faulty blower motor circuit wiring or wire har-
ness connectors.
VIBRATION
Possible causes of blower motor vibration include:
²Improper blower motor mounting
²Improper blower wheel mounting
²Blower wheel out of balance or bent
²Blower motor faulty.
NOISE
To verify that the blower is the source of the noise,
unplug the blower motor wire harness connector and
operate the HVAC system. If the noise goes away,
possible causes include:
²Foreign material in the HVAC housing
²Improper blower motor mounting
²Improper blower wheel mounting
²Blower motor faulty.
REMOVAL
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN AN ACCIDENTAL
AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
24 - 30 DISTRIBUTIONKJ