2002 JEEP GRAND CHEROKEE high output

tem functions, as well as separate hard wired sense
inputs to the BCM for the high speed continuous
wipe and front washer system functions.
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 on/off relay, and the park switch in the front
wiper motor. A separate fuse in the JB provides bat-
tery current through another fused ignition switch
output (run-acc) circuit to the right multi-function
switch. The right multi-function switch circuitry uses
this battery feed to directly control the operation of
the front washer pump/motor unit. The BCM uses
low side drivers to control front wiper system opera-
tion by energizing or de-energizing 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.
Following are paragraphs that briefly describe the
operation of each of the front wiper and washer sys-
tem operating modes.
CONTINUOUS WIPE MODE
When the Low position of the control knob on the
control stalk of the right (wiper) multi-function
switch is selected, the Body Control Module (BCM)
energizes the wiper on/off relay. This directs battery
current through the normally open contacts of the
energized wiper on/off relay and the normally closed
contacts of the de-energized wiper high/low relay to
the low speed brush of the front wiper motor, causing
the front wipers to cycle at low speed. When the
High position of the control knob is selected, the
BCM energizes both the wiper on/off relay and the
wiper high/low relay. This directs battery current
through the normally open contacts of the energized
wiper on/off relay and the normally open contacts of
the energized wiper high/low relay to the high speedbrush of the front wiper motor, causing the front wip-
ers to cycle at high speed.
When the Off position of the control knob is
selected, the BCM de-energizes both the wiper on/off
and wiper high/low relays, then one of two events
will occur. The event that will occur depends upon
the position of the wiper blades on the windshield at
the moment that the control knob Off position is
selected. If the wiper blades are in the down position
on the windshield when the Off position is selected,
the park switch that is integral to the front wiper
motor is closed to ground and the wiper motor ceases
to operate. If the wiper blades are not in the down
position on the windshield at the moment the Off
position is selected, the park switch is closed to bat-
tery current from the fused ignition switch output
(run-acc) circuit of the front wiper motor. The park
switch directs this battery current to the low speed
brush of the wiper motor through the wiper park
switch sense circuit and the normally closed contacts
of the wiper on/off and wiper high/low relays. This
causes the wiper motor to continue running at low
speed until the wiper blades are in the down position
on the windshield and the park switch is again
closed to ground.
INTERMITTENT WIPE MODE
On models not equipped with the optional auto-
matic wiper system, when the control knob on the
control stalk of the right (wiper) multi-function
switch is moved to one of the five Delay interval posi-
tions, the BCM electronic intermittent wipe logic cir-
cuit responds by calculating the correct length of
time between wiper sweeps based upon the selected
delay interval input. The BCM monitors the chang-
ing state of the wiper motor park switch through a
hard wired front wiper park switch sense circuit
input. This input allows the BCM to determine the
proper intervals at which to energize and de-energize
the wiper on/off relay to operate the front wiper
motor intermittently for one low speed cycle at a
time. The BCM logic is also programmed to provide
an immediate wipe cycle and begin a new delay
interval timing cycle each time a shorter delay inter-
val is selected, and to add the remaining delay tim-
ing interval to the new delay interval timing before
the next wipe cycle occurs each time a longer delay
interval is selected.
The intermittent wipe mode delay times are speed
sensitive. The BCM monitors vehicle speed messages
received from the Powertrain Control Module (PCM)
over the Programmable Communications Interface
(PCI) data bus network in order to provide the speed
sensitive delay intervals. Above about sixteen kilome-
ters-per-hour (ten miles-per-hour) the delay is driver
adjustable from about one-half second to about eigh-
WJFRONT WIPERS/WASHERS 8R - 5
FRONT WIPERS/WASHERS (Continued)

teen seconds. Below about sixteen kilometers-per-
hour (ten miles-per-hour) the delay times are
doubled, from about one second to about thirty-six
seconds.
AUTOMATIC WIPE MODE
On models equipped with the optional automatic
wiper system, when the control knob on the control
stalk of the right (wiper) multi-function switch is
moved to one of the five Auto sensitivity positions,
the BCM sends an electronic message to the Rain
Sensor Module (RSM) over the Programmable Com-
munications Interface (PCI) data bus network indi-
cating the selected position. The RSM monitors an
area within the wipe pattern of the windshield glass
for the accumulation of moisture. Based upon inter-
nal programming and the selected sensitivity level,
when sufficient moisture has accumulated the RSM
sends the appropriate electronic wipe command mes-
sages to the BCM over the PCI data bus and the
BCM operates the front wiper system accordingly. As
the sensitivity level is set higher, the RSM is more
sensitive to moisture accumulation and will send
wipe commands more frequently. The BCM logic is
also programmed to provide an immediate wipe cycle
each time the control knob on the control stalk of the
right multi-function switch is moved from a non-au-
tomatic wipe position to one of the five Auto sensitiv-
ity positions, and another immediate wipe cycle each
time the control knob is moved from a lower Auto
sensitivity position to a higher Auto sensitivity posi-
tion.
MIST WIPE MODE
When the control stalk of the right (wiper) multi-
function switch is moved to the momentary Mist
position, the BCM energizes the wiper on/off relay for
as long as the Mist switch is held closed, then de-en-
ergizes the relay when the state of the Mist switch
input changes to open. The BCM can operate the
front wiper motor in this mode for only one low speed
cycle at a time, or for an indefinite number of
sequential low speed cycles, depending upon how
long the Mist switch is held closed.
WASH MODE
When the control stalk of the right (wiper) multi-
function switch is moved to the momentary front
Wash position while the control knob is in the Low or
High positions, the circuitry within the switch directs
battery current to the front washer pump/motor unit.
This will cause the front washer pump/motor unit to
be energized for as long as the front Wash switch is
held closed, and to de-energize when the front Wash
switch is released. When the control stalk of the
right (wiper) multi-function switch is moved to the
momentary front Wash position while the controlknob is in one of the Delay interval or Auto sensitiv-
ity positions, the front washer pump/motor operation
is the same. However, the BCM energizes the wiper
on/off relay to override the selected delay interval or
auto sensitivity level and operate the front wiper
motor in a continuous low speed mode for as long as
the front Wash switch is held closed, then de-ener-
gizes the relay and reverts to the selected delay mode
interval or auto sensitivity level several wipe cycles
after the front Wash switch is released. The BCM
detects the front Wash switch state through a hard
wired washer pump motor switch output circuit input
from the right multi-function switch.
WIPE-AFTER-WASH MODE
When the control stalk of the right (wiper) multi-
function switch is moved to the momentary front
Wash position while the control knob is in the Off
position, the BCM detects that switch state through
a hard wired washer pump motor switch output cir-
cuit input from the right multi-function switch. The
BCM responds to this input by energizing the wiper
on/off relay for as long as the Wash switch is held
closed, then de-energizes the relay several wipe
cycles after the front Wash switch is released. The
BCM monitors the changing state of the wiper motor
park switch through a hard wired front wiper park
switch sense circuit input. This input allows the
BCM to count the number of wipe cycles that occur
after the front Wash switch state changes to open,
and to determine the proper interval at which to de-
energize the wiper on/off relay to complete the wipe-
after-wash mode cycle.
DIAGNOSIS AND TESTING - FRONT WIPER &
WASHER SYSTEM
FRONT WIPER SYSTEM
If the front wiper motor operates, but the wipers
do not move on the windshield, replace the faulty
front wiper module. If the wipers operate, but chat-
ter, lift, or do not clear the glass, clean and inspect
the wiper system components as required. (Refer to 8
- ELECTRICAL/FRONT WIPERS/WASHERS -
INSPECTION) and (Refer to 8 - ELECTRICAL/
FRONT WIPERS/WASHERS - CLEANING). Refer to
the appropriate wiring information. The wiring infor-
mation includes wiring diagrams, proper wire and
connector repair procedures, details of wire harness
routing and retention, connector pin-out information
and location views for the various wire harness con-
nectors, splices and grounds.
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-
8R - 6 FRONT WIPERS/WASHERSWJ
FRONT WIPERS/WASHERS (Continued)

ods may not prove conclusive in the diagnosis of the
Body Control Module (BCM), the Rain Sensor Mod-
ule (RSM), the Powertrain Control Module (PCM) or
the inputs to or outputs from these modules that con-
trol the various front wiper and washer system oper-
ating modes. The most reliable, efficient, and
accurate means to diagnose the BCM, the RSM, the
PCM 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.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE SUPPLEMENTAL RESTRAINT
SYSTEM BEFORE ATTEMPTING ANY STEERING
WHEEL, STEERING COLUMN, DRIVER AIRBAG,
PASSENGER AIRBAG, SIDE CURTAIN AIRBAG,
FRONT IMPACT SENSOR, SIDE IMPACT SENSOR,
OR INSTRUMENT PANEL COMPONENT DIAGNOSIS
OR SERVICE. DISCONNECT AND ISOLATE THE
BATTERY NEGATIVE (GROUND) CABLE, THEN
WAIT TWO MINUTES FOR THE SYSTEM CAPACI-
TOR TO DISCHARGE BEFORE PERFORMING FUR-
THER DIAGNOSIS OR SERVICE. THIS IS THE ONLY
SURE WAY TO DISABLE THE SUPPLEMENTAL
RESTRAINT SYSTEM. FAILURE TO TAKE THE
PROPER PRECAUTIONS COULD RESULT IN ACCI-
DENTAL AIRBAG DEPLOYMENT AND POSSIBLE
PERSONAL INJURY.
FRONT WASHER SYSTEM
The diagnosis found here addresses an electrically
inoperative washer system. If the washer pump/mo-
tor operates, but no washer fluid is emitted from the
front washer nozzles, be certain to check the fluid
level in the reservoir. Also inspect the front washer
system components as required. (Refer to 8 - ELEC-
TRICAL/FRONT WIPERS/WASHERS - INSPEC-
TION). Refer to the appropriate wiring information.
The wiring information includes wiring diagrams,
proper wire and connector repair procedures, details
of wire harness routing and retention, connector pin-
out information and location views for the various
wire harness connectors, splices and grounds.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE SUPPLEMENTAL RESTRAINT
SYSTEM BEFORE ATTEMPTING ANY STEERING
WHEEL, STEERING COLUMN, DRIVER AIRBAG,
PASSENGER AIRBAG, SIDE CURTAIN AIRBAG,
FRONT IMPACT SENSOR, SIDE IMPACT SENSOR,
OR INSTRUMENT PANEL COMPONENT DIAGNOSIS
OR SERVICE. DISCONNECT AND ISOLATE THE
BATTERY NEGATIVE (GROUND) CABLE, THEN
WAIT TWO MINUTES FOR THE SYSTEM CAPACI-
TOR TO DISCHARGE BEFORE PERFORMING FUR-THER DIAGNOSIS OR SERVICE. THIS IS THE ONLY
SURE WAY TO DISABLE THE SUPPLEMENTAL
RESTRAINT SYSTEM. FAILURE TO TAKE THE
PROPER PRECAUTIONS COULD RESULT IN ACCI-
DENTAL AIRBAG DEPLOYMENT AND POSSIBLE
PERSONAL INJURY.
(1) Turn the ignition switch to the On position.
Turn the control knob on the control stalk of the
right (wiper) multi-function switch to the Low or
High wiper position. Check whether the front wiper
system is operating. If OK, go to Step 2. If not OK,
test and repair the front wiper system before con-
tinuing with these tests. Refer to FRONT WIPER
SYSTEM
(2) Turn the control knob on the control stalk of
the right (wiper) multi-function switch to the Off
position. Pull the control stalk of the right (wiper)
multi-function switch toward the steering wheel to
close the front washer switch. The front washer
pump should operate and the front wipers should
operate for about three sweep cycles after the switch
is released before they park. If the front wipers are
OK, but the front washers are not, go to Step 3. If
the front washers are OK, but the front wipers are
not, go to Step 5.
(3) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Disconnect the left headlamp and dash wire harness
connector for the front washer pump/motor from the
pump/motor connector receptacle. Check for continu-
ity between the ground circuit cavity of the left head-
lamp and dash wire harness connector for the front
washer pump/motor and a good ground. There should
be continuity. If OK, go to Step 4. If not OK, repair
the open ground circuit to ground (G106) as required.
(4) Reconnect the battery negative cable. Turn the
ignition switch to the On position. While pulling the
control stalk of the right (wiper) multi-function
switch toward the steering wheel to close the front
washer switch, check for battery voltage at the
washer pump switch sense circuit cavity of the left
headlamp and dash wire harness connector for the
front washer pump/motor unit. If OK, replace the
faulty front washer pump/motor. If not OK, repair
the open washer pump switch sense circuit between
the right (wiper) multi-function switch and the front
washer pump/motor unit as required.
(5) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Disconnect the instrument panel wire harness con-
nector (Connector C2) for the Body Control Module
(BCM) from the BCM connector receptacle. Recon-
nect the battery negative cable. Turn the ignition
switch to the On position. While pulling the control
stalk of the right (wiper) multi-function switch
toward the steering wheel to close the front washer
WJFRONT WIPERS/WASHERS 8R - 7
FRONT WIPERS/WASHERS (Continued)

(3) Insert the hook formation on the tip of the
wiper arm through the opening in the wiper blade
superstructure ahead of the wiper blade pivot block/
latch unit far enough to engage the pivot block with
the hook (Fig. 10).
(4) Slide the wiper blade pivot block/latch up into
the hook formation on the tip of the wiper arm until
the latch release tab snaps into its locked position.
Latch engagement will be accompanied by an audible
click.
(5) Gently lower the wiper blade onto the glass.
FRONT WIPER MODULE
DESCRIPTION
The front wiper module is secured with four screws
through rubber isolators to the cowl plenum panel
beneath the cowl plenum cover/grille panel (Fig. 11).
The ends of the wiper pivot shafts that protrude
through dedicated openings in the cowl plenum cov-
er/grille panel to drive the wiper arms and blades are
the only visible components of the front wiper mod-
ule. The front wiper module consists of the following
major components:
²Bracket- The front wiper module bracket con-
sists of a long tubular steel main member that has a
stamped pivot bracket formation near each end
where the two wiper pivots are secured. A stamped
steel mounting plate for the wiper motor is secured
with welds near the center of the main member.
²Crank Arm- The front wiper motor crank arm
is a stamped steel unit with a slotted hole on the
driven end that is secured to the wiper motor outputshaft with a nut, and a ball stud secured to the drive
end.
²Linkage- Two stamped steel drive links con-
nect the wiper motor crank arm to the pivot lever
arms. The passenger side drive link has a plastic
socket-type bushing on each end. The driver side
drive link has a plastic socket-type bushing on one
end, and a plastic sleeve-type bushing on the other
end. The socket-type bushing on one end of each
drive link is snap-fit over the ball stud on the lever
arm of its respective pivot. The driver side drive link
sleeve-type bushing end is then fit over the motor
crank arm ball stud, and the other socket-type bush-
ing of the passenger side drive link is snap-fit over
the exposed end of the wiper motor crank arm ball
stud.
²Motor- The front wiper motor is secured with
three screws to the motor mounting plate near the
center of the wiper module bracket. The wiper motor
output shaft passes through a hole in the module
bracket, where a nut secures the wiper motor crank
arm to the motor output shaft. The two-speed perma-
nent magnet wiper motor features an integral trans-
mission, an internal park switch, and an internal
automatic resetting circuit breaker.
²Pivots- The two front wiper pivots are secured
to the ends of the wiper module bracket. The crank
arms that extend from the bottom of the pivot shafts
each have a ball stud on their end. The upper end of
each pivot shaft where the wiper arms will be fas-
tened each has an externally serrated drum with a
threaded stud secured to it.
The front wiper module cannot be adjusted or
repaired. If any component of the module is faulty or
damaged, the entire front wiper module unit must be
replaced. The reinforcement bracket and stud plate
are available for service replacement.OPERATION
The front wiper module operation is controlled by
the battery current inputs received by the wiper
motor from the wiper on/off and wiper high/low
relays. The wiper motor speed is controlled by cur-
rent flow to either the low speed or the high speed
set of brushes. The park switch is a single pole, sin-
gle throw, momentary switch within the wiper motor
that is mechanically actuated by the wiper motor
transmission components. The park switch alter-
nately closes the wiper park switch sense circuit to
ground or to battery current, depending upon the
position of the wipers on the glass. This feature
allows the motor to complete its current wipe cycle
after the wiper system has been turned Off, and to
park the wiper blades in the lowest portion of the
wipe pattern. The automatic resetting circuit breaker
protects the motor from overloads. The wiper motor
Fig. 11 Front Wiper Module
1 - FRONT WIPER MODULE
2 - SCREW (4)
3 - WIRE HARNESS CONNECTOR
4 - LOWER COWL PLENUM PANEL
8R - 16 FRONT WIPERS/WASHERSWJ
FRONT WIPER BLADE (Continued)

²Continuous Rear Wipe Mode- The internal
circuitry and hardware of the right (wiper) multi-
function switch control sleeve provides one continu-
ous rear wipe switch position.
²Front Washer Mode- The internal circuitry
and hardware of the right (wiper) multi-function
switch control stalk provide front washer system
operation.
²Front Wipe-After-Wash Mode- The internal
circuitry and hardware of the right (wiper) multi-
function switch control stalk provide a wipe-after-
wash mode.
²Front Wiper Mist Mode- The internal cir-
cuitry and hardware of the right (wiper) multi-func-
tion switch control stalk provide a front wiper system
mist mode.
²Intermittent Front Wipe Mode- The internal
circuitry and hardware of the right (wiper) multi-
function switch control knob provide an intermittent
front wipe mode with five delay interval positions,
except on models equipped with the optional auto-
matic wiper system.
²Intermittent Rear Wipe Mode- The internal
circuitry and hardware of the right (wiper) multi-
function switch control ring provide one fixed inter-
val intermittent rear wipe mode switch position.
²Rear Washer Mode- The internal circuitry and
hardware of the right (wiper) multi-function switch
control stalk provide rear washer system operation.
OPERATION
The right (wiper) multi-function switch uses a com-
bination of resistor multiplexed and conventionally
switched outputs to control the many functions and
features it provides. The switch receives battery cur-
rent on a fused ignition switch output (run-acc) cir-
cuit from a fuse in the Junction Block (JB) whenever
the ignition switch is in the On or Accessory posi-
tions, and receives ground from the Body Control
Module (BCM) on a windshield wiper switch return
circuit. The right (wiper) multi-function switch may
be diagnosed using conventional diagnostic tools and
methods.
Following are descriptions of how the right (wiper)
multi-function switch control stalk operates to control
the functions and features it provides:
²Automatic Wipe Mode- On models equipped
with the optional automatic wiper system, the control
knob on the end of the right (wiper) multi-function
switch control stalk is rotated to one of five minor
intermediate detents to select the desired automatic
wipe sensitivity level. The control knob is rotated
rearward (counterclockwise) to reduce the sensitivity
(increase the interval between wipes), or forward
(clockwise) to increase the sensitivity (decrease the
interval between wipes). The right (wiper) multi-function switch provides a resistor multiplexed out-
put to the Body Control Module (BCM) on a
windshield wiper switch mux circuit. The BCM
responds by sending an electronic message to the
Rain Sensor Module (RSM) over the Programmable
Communications Interface (PCI) data bus indicating
the selected sensitivity level, and by operating the
front wiper system based upon electronic wipe com-
mands received from the RSM over the PCI data bus.
²Continuous Front Wipe Modes- The control
knob on the end of the right (wiper) multi-function
switch control stalk is rotated to an intermediate
detent that is one detent rearward (counterclockwise)
from the full forward (clockwise) detent to select the
low speed continuous front wiper mode, or to its full
forward (clockwise) detent to select the high speed
continuous front wiper mode. For the low speed
mode, the multi-function switch provides a resistor
multiplexed output to the Body Control Module
(BCM) on a windshield wiper switch mux circuit, and
the BCM responds by energizing the wiper on/off
relay in the Power Distribution Center (PDC) for the
front low speed continuous wipe mode. For the high
speed mode, the multi-function switch provides the
same resistor multiplexed output to the BCM on the
windshield wiper switch mux circuit as the low speed
mode, but also provides a ground output to the BCM
on a wiper high control circuit. The BCM responds to
these inputs by energizing the wiper on/off relay and
the wiper high/low relay in the PDC for the front
high speed continuous wipe mode.
²Continuous Rear Wipe Mode- The control
ring on the right (wiper) multi-function switch con-
trol stalk is rotated to the most forward (clockwise)
detent to select the continuous rear wiper mode. The
multi-function switch provides a battery current out-
put to the rear wiper motor on a rear wiper motor
control circuit to signal the rear wiper module to
operate the rear wiper motor in the continuous wipe
mode.
²Front Washer Mode- The control stalk of the
right (wiper) multi-function switch is pulled toward
the steering wheel to momentarily activate the front
washer pump/motor in the front washer mode. The
front washer pump will continue to operate in the
front washer mode until the control stalk is released.
The right (wiper) multi-function switch provides a
battery current output on a washer pump motor
switch output circuit to energize the front washer
pump in the front washer mode.
²Front Wiper Mist Mode- The control stalk of
the right (wiper) multi-function switch is pushed
towards the floor to momentarily activate the front
wiper motor in the mist mode. The front wiper motor
will continue to operate in the mist mode until the
control stalk is released. The right (wiper) multi-
WJFRONT WIPERS/WASHERS 8R - 21
RIGHT MULTI-FUNCTION SWITCH (Continued)

(6) Install and tighten the two screws that secure
the inboard mounting flange of the washer reservoir
to the left inner wheel house. Tighten the screws to
7.4 N´m (66 in. lbs.).
(7) Reconnect the left headlamp and dash wire
harness connectors for the two washer pump/motor
units to the pump/motor unit connector receptacles.
(8) Reinstall the liner into the left front fender
wheel house.
(9) Lower the vehicle.
(10) Install and tighten the one screw that secures
the washer reservoir filler neck to the left inner
fender shield (Fig. 23). Tighten the screw to 7.4 N´m
(66 in. lbs.).
(11) Reinstall the washer reservoir filler cap hinge
onto the hook on the filler neck and close the cap.
(12) Reconnect the two washer reservoir washer
hoses to the two engine compartment washer hoses
at the inline connectors located on the top of the left
front fender wheel house.
(13) Reinstall the air cleaner housing onto the top
of the left front fender wheel house. (Refer to 9 -
ENGINE/AIR INTAKE SYSTEM/AIR CLEANER
HOUSING - INSTALLATION).
(14) 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 the
ISO 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.
Fig. 25 ISO Micro Relay
30 - COMMON FEED
85 - COIL GROUND
86 - COIL BATTERY
87 - NORMALLY OPEN
87A - NORMALLY CLOSED
WJFRONT WIPERS/WASHERS 8R - 29
WASHER RESERVOIR (Continued)

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.
²Normally Closed Terminal- The normally
closed terminal (87A) is connected to the low speed
brush of the front wiper motor through a front wiper
high/low relay low speed output circuit, and is con-
nected to the low speed brush whenever the relay is
de-energized.
The wiper high/low relay can be diagnosed using
conventional diagnostic tools and methods.
DIAGNOSIS AND TESTING - WIPER HIGH/LOW
RELAY
The wiper high/low relay (Fig. 26) is located in the
Power Distribution Center (PDC) in the engine com-
partment near the battery. Refer to the appropriate
wiring information. The wiring information includes
wiring diagrams, proper wire and connector repair
procedures, details of wire harness routing and
retention, connector pin-out information and location
views for the various wire harness connectors, splices
and grounds.
(1) Remove the wiper high/low relay from the
PDC. (Refer to 8 - ELECTRICAL/WIPERS/WASH-
ERS/WIPER HIGH/LOW RELAY - REMOVAL).
(2) A relay in the de-energized position should
have continuity between terminals 87A and 30, andno continuity between terminals 87 and 30. If OK, go
to Step 3. If not OK, replace the faulty relay.
(3) Resistance between terminals 85 and 86 (elec-
tromagnet) should be 75   8 ohms. If OK, go to Step
4. If not OK, replace the faulty relay.
(4) 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, reinstall the relay and use a DRBIIIt
scan tool to perform further testing. Refer to the
appropriate diagnostic information.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the cover from the Power Distribution
Center (PDC) (Fig. 27).
(3) See the fuse and relay layout label affixed to
the underside of the PDC cover for wiper high/low
relay identification and location.
(4) Remove the wiper high/low relay by grasping it
firmly and pulling it straight out from the receptacle
in the PDC.
INSTALLATION
(1) See the fuse and relay layout label affixed to
the underside of the PDC cover for the proper wiper
high/low relay location (Fig. 27).
Fig. 26 ISO Micro Relay
30 - COMMON FEED
85 - COIL GROUND
86 - COIL BATTERY
87 - NORMALLY OPEN
87A - NORMALLY CLOSED
Fig. 27 Power Distribution Center
1 - RIGHT FENDER
2 - BATTERY
3 - POWER DISTRIBUTION CENTER
4 - COVER
8R - 30 FRONT WIPERS/WASHERSWJ
WIPER HIGH/LOW RELAY (Continued)

(2) Position the wiper high/low relay in the proper
receptacle in the PDC.
(3) Align the wiper high/low relay terminals with
the terminal cavities in the PDC receptacle.
(4) Push firmly and evenly on the top of the wiper
high/low relay until the terminals are fully seated in
the terminal cavities in the PDC receptacle.
(5) Reinstall the cover onto the PDC.
(6) Reconnect the battery negative cable.
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
WJFRONT WIPERS/WASHERS 8R - 31
WIPER HIGH/LOW RELAY (Continued)