1998 DODGE RAM 1500 Fluid

required. Refer to the appropriate diagnostic infor-
mation.
TRANS TEMP INDICATOR
DESCRIPTION
A transmission over-temperature indicator is stan-
dard equipment on all instrument clusters (Fig. 31).
However, on vehicles not equipped with an optional
automatic transmission, this indicator is electroni-
cally disabled. The transmission over-temperature
indicator is located on the left side of the instrument
cluster, to the left of the fuel gauge. The transmission
over-temperature indicator consists of a stencil-like
cutout of the words ªTRANS TEMPº in the opaque
layer of the instrument cluster overlay. The dark
outer layer of the overlay prevents the indicator from
being clearly visible when it is not illuminated. A red
Light Emitting Diode (LED) behind the cutout in the
opaque layer of the overlay causes the ªTRANS
TEMPº text to appear in red through the translucent
outer layer of the overlay when the indicator is illu-
minated from behind by the LED, which is soldered
onto the instrument cluster electronic circuit board.
The transmission over-temperature indicator is ser-
viced as a unit with the instrument cluster.
OPERATION
The transmission over-temperature indicator gives
an indication to the vehicle operator when the trans-
mission fluid temperature is excessive, which may
lead to accelerated transmission component wear or
failure. This indicator is controlled by a transistor on
the instrument cluster circuit board based upon clus-
ter programming and electronic messages received by
the cluster from the Powertrain Control Module
(PCM) over the Programmable Communications
Interface (PCI) data bus. The transmission over-tem-
perature indicator Light Emitting Diode (LED) is
completely controlled by the instrument cluster logic
circuit, and that logic will only allow this indicator to
operate when the instrument cluster receives a bat-
tery current input on the fused ignition switch out-
put (run-start) circuit. Therefore, the LED will
always be off when the ignition switch is in any posi-
tion except On or Start. The LED only illuminates
when it is provided a path to ground by the instru-
ment cluster transistor. The instrument cluster will
turn on the transmission over-temperature indicator
for the following reasons:²Bulb Test- Each time the ignition switch is
turned to the On position the transmission over-tem-
perature indicator is illuminated for about two sec-
onds as a bulb test.
²Trans Over-Temp Lamp-On Message- Each
time the cluster receives a trans over-temp lamp-on
message from the PCM indicating that the transmis-
sion fluid temperature is 135É C (275É F) or higher,
the indicator will be illuminated and a single chime
tone is sounded. The indicator remains illuminated
until the cluster receives a trans over-temp lamp-off
message from the PCM, or until the ignition switch
is turned to the Off position, whichever occurs first.
The chime tone feature will only repeat during the
same ignition cycle if the transmission over-tempera-
ture indicator is cycled off and then on again by the
appropriate trans over-temp messages from the PCM.
²Actuator Test- Each time the cluster is put
through the actuator test, the transmission over-tem-
perature indicator will be turned on, then off again
during the bulb check portion of the test to confirm
the functionality of the LED and the cluster control
circuitry.
The PCM continually monitors the transmission
temperature sensor to determine the transmission
operating condition. The PCM then sends the proper
trans over-temp lamp-on or lamp-off messages to the
instrument cluster. If the instrument cluster turns on
the transmission over-temperature indicator due to a
high transmission oil temperature condition, it may
indicate that the transmission and/or the transmis-
sion cooling system are being overloaded or that they
require service. For further diagnosis of the trans-
mission over-temperature indicator or the instrument
cluster circuitry that controls the LED, (Refer to 8 -
ELECTRICAL/INSTRUMENT CLUSTER - DIAGNO-
SIS AND TESTING). For proper diagnosis of the
transmission temperature sensor, the PCM, the PCI
data bus, or the electronic message inputs to the
instrument cluster that control the transmission
over-temperature indicator, a DRBIIItscan tool is
required. Refer to the appropriate diagnostic infor-
mation.
TURN SIGNAL INDICATOR
DESCRIPTION
Two turn signal indicators, one right and one left,
are standard equipment on all instrument clusters
(Fig. 32). The turn signal indicators are located near
Fig. 31 Transmission Overtemp Indicator
Fig. 32 Turn Signal Indicators
8J - 40 INSTRUMENT CLUSTERDR
TOW/HAUL INDICATOR (Continued)

WAIT-TO-START INDICATOR
DESCRIPTION
A wait-to-start indicator is only found in the
instrument clusters for vehicles equipped with an
optional diesel engine (Fig. 35). The wait-to-start
indicator is located near the lower edge of the instru-
ment cluster, between the tachometer and the speed-
ometer. The wait-to-start indicator consists of stencil-
like cutout of the International Control and Display
Symbol icon for ªDiesel Preheatº in the opaque layer
of the instrument cluster overlay. The dark outer
layer of the overlay prevents the indicator from being
clearly visible when it is not illuminated. An amber
Light Emitting Diode (LED) behind the cutout in the
opaque layer of the overlay causes the icon to appear
in amber through the translucent outer layer of the
overlay when the indicator is illuminated from
behind by the LED, which is soldered onto the
instrument cluster electronic circuit board. The wait-
to-start indicator is serviced as a unit with the
instrument cluster.
OPERATION
The wait-to-start indicator gives an indication to
the vehicle operator when the air temperature within
the diesel engine intake manifold is too cool for effi-
cient and reliable engine starting, and that the
intake air heater grids are energized in their pre-
heat operating mode. This indicator is controlled by a
transistor on the instrument cluster circuit board
based upon cluster programming and electronic mes-
sages received by the cluster from the Engine Control
Module (ECM) over the Programmable Communica-
tions Interface (PCI) data bus. The wait-to-start indi-
cator Light Emitting Diode (LED) is completely
controlled by the instrument cluster logic circuit, and
that logic will only allow this indicator to operate
when the instrument cluster receives a battery cur-
rent input on the fused ignition switch output (run-
start) circuit. Therefore, the LED will always be off
when the ignition switch is in any position except On
or Start. The LED only illuminates when it is pro-
vided a path to ground by the instrument cluster
transistor. The instrument cluster will turn on the
wait-to-start indicator for the following reasons:
²Wait-To-Start Lamp-On Message- Each time
the cluster receives a wait-to-start lamp-on message
from the ECM indicating that the air temperature
within the intake manifold is too cool for efficient
and reliable engine starting, the wait-to-start indica-
tor will be illuminated. The indicator remains illumi-nated until the cluster receives a wait-to-start lamp-
off message, until the ECM detects that the engine is
running or until the ignition switch is turned to the
Off position, whichever occurs first.
²Actuator Test- Each time the cluster is put
through the actuator test, the wait-to-start indicator
will be turned on, then off again during the bulb
check portion of the test to confirm the functionality
of the LED and the cluster control circuitry.
The ECM continually monitors the engine intake
air temperature sensor to determine when the intake
air heater grids should be energized in their pre-heat
operating mode. The ECM then sends the proper
wait-to-start lamp-on and lamp-off messages to the
instrument cluster. For further diagnosis of the wait-
to-start indicator or the instrument cluster circuitry
that controls the indicator, (Refer to 8 - ELECTRI-
CAL/INSTRUMENT CLUSTER - DIAGNOSIS AND
TESTING). For proper diagnosis of the engine intake
air temperature sensor, the intake air heater grid
control circuits, the ECM, the PCI data bus, or the
electronic message inputs to the instrument cluster
that control the wait-to-start indicator, a DRBIIIt
scan tool is required. Refer to the appropriate diag-
nostic information.
WASHER FLUID INDICATOR
DESCRIPTION
A washer fluid indicator is standard equipment on
all instrument clusters. The washer fluid indicator
consists of the words ªLOW WASHº, which appear in
the lower portion of the odometer/trip odometer Vac-
uum-Fluorescent Display (VFD) unit (Fig. 36). The
VFD is soldered onto the cluster electronic circuit
board and is visible through a window with a smoked
clear lens located on the lower edge of the tachome-
ter gauge dial face of the cluster overlay. The dark
lens over the VFD prevents the indicator from being
clearly visible when it is not illuminated. The ªLOW
WASHº text appears in an amber color and at the
same lighting level as the odometer/trip odometer
information when it is illuminated by the instrument
cluster electronic circuit board. The washer fluid
indicator is serviced as a unit with the VFD in the
instrument cluster.
OPERATION
The washer fluid indicator gives an indication to
the vehicle operator that the fluid level in the washer
Fig. 35 Wait-To-Start Indicator
Fig. 36 Washer Fluid Indicator
8J - 44 INSTRUMENT CLUSTERDR

reservoir is low. This indicator is controlled by the
instrument cluster circuit board based upon cluster
programming and electronic messages received by
the cluster from the Front Control Module (FCM)
over the Programmable Communications Interface
(PCI) data bus. The washer fluid indicator is com-
pletely controlled by the instrument cluster logic cir-
cuit, and that logic will only allow this indicator to
operate when the instrument cluster receives a bat-
tery current input on the fused ignition switch out-
put (run-start) circuit. Therefore, the indicator will
always be off when the ignition switch is in any posi-
tion except On or Start. The indicator only illumi-
nates when it is switched to ground by the
instrument cluster circuitry. The instrument cluster
will turn on the washer fluid indicator for the follow-
ing reasons:
²Washer Fluid Indicator Lamp-On Message-
Each time the cluster receives a washer fluid indica-
tor lamp-on message from the FCM indicating that a
low washer condition has been detected for sixty con-
secutive seconds, the washer fluid indicator is illumi-
nated and a single chime tone is sounded. The
indicator remains illuminated until the cluster
receives a washer fluid indicator lamp-off message
for sixty consecutive seconds from the FCM or until
the ignition switch is turned to the Off position,
whichever occurs first. The chime tone feature will
only repeat during the same ignition cycle if the
washer fluid indicator is cycled off and then on again
by the appropriate washer fluid lamp messages from
the FCM.
²Actuator Test- Each time the cluster is put
through the actuator test, the washer fluid indicator
will be turned on, then off again during the VFD por-
tion of the test to confirm the functionality of the
VFD and the cluster control circuitry.
The FCM continually monitors the washer fluid
level switch in the washer reservoir to determine the
level of the washer fluid. The FCM then sends the
proper washer fluid indicator lamp-on and lamp-off
messages to the instrument cluster. For further diag-
nosis of the washer fluid indicator or the instrument
cluster circuitry that controls the indicator, (Refer to
8 - ELECTRICAL/INSTRUMENT CLUSTER - DIAG-
NOSIS AND TESTING). For proper diagnosis of the
washer fluid level switch, the FCM, the PCI data
bus, or the electronic message inputs to the instru-
ment cluster that control the washer fluid indicator,
a DRBIIItscan tool is required. Refer to the appro-
priate diagnostic information.WATER-IN-FUEL INDICATOR
DESCRIPTION
A water-in-fuel indicator is only found in the
instrument clusters for vehicles equipped with an
optional diesel engine (Fig. 37). The water-in-fuel
indicator is located near the lower edge of the instru-
ment cluster, between the tachometer and the speed-
ometer. The water-in-fuel indicator consists of stencil-
like cutout of the International Control and Display
Symbol icon for ªWater In Fuelº in the opaque layer
of the instrument cluster overlay. The dark outer
layer of the overlay prevents the indicator from being
clearly visible when it is not illuminated. A red Light
Emitting Diode (LED) behind the cutout in the
opaque layer of the overlay causes the icon to appear
in red through the translucent outer layer of the
overlay when the indicator is illuminated from
behind by the LED, which is soldered onto the
instrument cluster electronic circuit board. The
water-in-fuel indicator is serviced as a unit with the
instrument cluster.
OPERATION
The water-in-fuel indicator gives an indication to
the vehicle operator when there is excessive water in
the fuel system. This indicator is controlled by a
transistor on the instrument cluster circuit board
based upon the cluster programming and electronic
messages received by the cluster from the Engine
Control Module (ECM) over the Programmable Com-
munications Interface (PCI) data bus. The water-in-
fuel indicator Light Emitting Diode (LED) is
completely controlled by the instrument cluster logic
circuit, and that logic will only allow this indicator to
operate when the instrument cluster receives a bat-
tery current input on the fused ignition switch out-
put (run-start) circuit. Therefore, the LED will
always be off when the ignition switch is in any posi-
tion except On or Start. The LED only illuminates
when it is provided a path to ground by the instru-
ment cluster transistor. The instrument cluster will
turn on the water-in-fuel indicator for the following
reasons:
²Bulb Test- Each time the ignition switch is
turned to the On position the water-in-fuel indicator
is illuminated for about two seconds as a bulb test.
²Water-In-Fuel Lamp-On Message- Each time
the cluster receives a water-in-fuel lamp-on message
from the ECM indicating that there is excessive
Fig. 37 Water-In-Fuel Indicator
DRINSTRUMENT CLUSTER 8J - 45
WASHER FLUID INDICATOR (Continued)

WIPERS/WASHERS
TABLE OF CONTENTS
page page
WIPERS/WASHERS
DESCRIPTION..........................1
OPERATION............................4
DIAGNOSIS AND TESTING - WIPER &
WASHER SYSTEM.....................6
CLEANING - WIPER & WASHER SYSTEM.....6
INSPECTION - WIPER & WASHER SYSTEM . . . 7
CHECK VALVE
DESCRIPTION..........................7
OPERATION............................8
REMOVAL.............................8
INSTALLATION..........................8
WASHER FLUID LEVEL SWITCH
DESCRIPTION..........................9
OPERATION............................9
REMOVAL.............................10
INSTALLATION.........................11
WASHER HOSES/TUBES
DESCRIPTION.........................11
OPERATION...........................11
WASHER NOZZLE
DESCRIPTION.........................11
OPERATION...........................12
REMOVAL.............................12
INSTALLATION.........................12
WASHER PUMP/MOTOR
DESCRIPTION.........................13
OPERATION...........................13
REMOVAL.............................14
INSTALLATION.........................14
WASHER RESERVOIR
DESCRIPTION.........................14
OPERATION...........................15
REMOVAL
REMOVAL - EXCEPT DIESEL ENGINE.....15REMOVAL - DIESEL ENGINE............16
INSTALLATION
INSTALLATION - EXCEPT DIESEL ENGINE . . 17
INSTALLATION - DIESEL ENGINE.........17
WIPER ARM
DESCRIPTION.........................17
OPERATION...........................18
REMOVAL.............................18
INSTALLATION.........................18
WIPER BLADE
DESCRIPTION.........................18
OPERATION...........................19
REMOVAL.............................19
INSTALLATION.........................20
WIPER HIGH/LOW RELAY
DESCRIPTION.........................20
OPERATION...........................20
DIAGNOSIS AND TESTING - WIPER HIGH/
LOW RELAY.........................21
REMOVAL.............................21
INSTALLATION.........................22
WIPER MODULE
DESCRIPTION.........................22
OPERATION...........................23
REMOVAL.............................23
INSTALLATION.........................23
WIPER ON/OFF RELAY
DESCRIPTION.........................24
OPERATION...........................25
DIAGNOSIS AND TESTING - WIPER ON/OFF
RELAY..............................25
REMOVAL.............................26
INSTALLATION.........................26
WIPERS/WASHERS
DESCRIPTION
An electrically operated intermittent wiper and
washer system is standard factory-installed safety
equipment on this model (Fig. 1). The wiper and
washer system includes the following major compo-
nents, which are described in further detail else-
where in this service information:
²Check Valve- The washer system check valve
is integral to the wye fitting located in the washer
plumbing between the cowl plenum washer hose andthe washer nozzles, and is concealed beneath the
cowl plenum cover/grille panel at the base of the
windshield.
²Front Control Module- The Front Control
Module (FCM) is integral to the Integrated Power
Module (IPM). The IPM is located in the engine com-
partment, near the battery. (Refer to 8 - ELECTRI-
CAL/POWER DISTRIBUTION/INTEGRATED
POWER MODULE - DESCRIPTION).
²Instrument Cluster- In this model, the instru-
ment cluster is also sometimes referred to as the Cab
Control Node (CCN). The instrument cluster is
located in the instrument panel above the steering
DRWIPERS/WASHERS 8R - 1

column opening, directly in front of the driver. (Refer
to 8 - ELECTRICAL/INSTRUMENT CLUSTER -
DESCRIPTION).
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 control stalk that extends through
an opening on the left side of the steering column
shrouds and a control knob on the end of the stalk is
dedicated to providing all of the driver controls for
the wiper and washer systems. (Refer to 8 - ELEC-
TRICAL/LAMPS/LIGHTING - EXTERIOR/MULTI-
FUNCTION SWITCH - DESCRIPTION).
²Washer Fluid Level Switch- The washer fluid
level switch is located in a dedicated hole on the out-
board side of the washer reservoir in the engine com-
partment.²Washer Nozzle- Two fluidic washer nozzles are
secured with integral snap features to dedicated
openings in the cowl plenum cover/grille panel
located near the base of the windshield.
²Washer Plumbing- The plumbing for the
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 a trough near the
right end of the cowl plenum cover/grille panel into
the cowl plenum to the washer nozzle fittings.
²Washer Pump/Motor- The electric washer
pump/motor unit is located in a dedicated hole on the
rearward facing surface of the washer reservoir in
the engine compartment.
²Washer Reservoir- On all models except those
with an optional diesel engine, the washer reservoir
Fig. 1 Wiper & Washer System
1 - WASHER RESERVOIR, PUMP/MOTOR, FLUID LEVEL
SWITCH (EXCEPT DIESEL ENGINE)
2 - WASHER RESERVOIR, PUMP/MOTOR, FLUID LEVEL
SWITCH (DIESEL ENGINE ONLY)3 - WIPER MODULE
4 - WASHER NOZZLE (2)
5 - WIPER ARM & BLADE (2)
6 - MULTI-FUNCTION (WIPER, WASHER, & LIGHTING) SWITCH
8R - 2 WIPERS/WASHERSDR
WIPERS/WASHERS (Continued)

is secured by integral mounting tabs and a snap fea-
ture to slots in the right side of the cooling module
shroud in the engine compartment. On models with
an optional diesel engine, the washer reservoir is
secured by screws to the back of the upright left ver-
tical member of the radiator support in the engine
compartment. The washer reservoir filler neck is
accessed from the engine compartment.
²Wiper Arm- The two wiper arms are secured
with integral latches to the serrated ends of the two
wiper pivot shafts, which extend through the cowl
plenum cover/grille panel located near the base of the
windshield.
²Wiper Blade- The two wiper blades are
secured to the two wiper arms with an integral latch,
and are parked on the glass near the bottom of the
windshield when the wiper system is not in opera-
tion.
²Wiper High/Low Relay- The wiper high/low
relay is an International Standards Organization
(ISO) micro relay located in the Integrated Power
Module (IPM) in the engine compartment near the
battery.
²Wiper Module- The wiper pivot shafts are the
only visible components of the wiper module. The
remainder of the module is concealed within the cowl
plenum area beneath the cowl plenum cover/grille
panel. The wiper module includes the wiper module
bracket, four rubber-isolated wiper module mounts,
the wiper motor, the wiper motor crank arm, the two
wiper drive links, and the two wiper pivots.
²Wiper On/Off Relay- The wiper on/off relay is
an International Standards Organization (ISO) micro
relay located in the Integrated Power Module (IPM)
in the engine compartment near the battery.
Hard wired circuitry connects the 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 wiper and washer
system components through the use of a combination
of soldered splices, splice block connectors, and many
different types of wire harness terminal connectors
and insulators. Refer to the appropriate wiring infor-
mation. The wiring information includes wiring dia-
grams, proper wire and connector repair procedures,
further details on wire harness routing and reten-
tion, as well as pin-out and location views for the
various wire harness connectors, splices and grounds.
OPERATING MODES
The components of the wiper and washer system
are designed to work in concert to provide the follow-
ing operating modes:²Continuous Wipe Mode- The control knob on
the 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 wiper motor to operate in a continuous low or
high speed cycle.
²Intermittent Wipe Mode- The control knob on
the control stalk of the multi-function switch has five
minor detent intermittent wipe positions. When
selected, these switch positions will cause the wiper
system to operate with one of five delay intervals
between complete wipe cycles. The intermittent wipe
delay intervals are speed sensitive and will be dou-
bled when the vehicle speed is about sixteen kilome-
ters-per-hour (ten miles-per-hour) or less.
²Pulse Wipe Mode- When the control knob on
the control stalk of the multi-function switch is
depressed to the momentary Wash position for less
than about one-half second, the wiper system will
operate the wipers for one complete low speed cycle,
then will park the wiper blades near the base of the
windshield.
²Washer Mode- When the control knob on the
control stalk of the multi-function switch is
depressed to the momentary Wash position for more
than about one-half second with the wiper system
turned Off, the washer pump/motor and the wipers
will operate for as long as the washer switch is held
closed up to about thirty seconds, then the wipe-af-
ter-wash mode is invoked when the control knob is
released. When the Wash position is selected with
the wiper system operating in a continuous wipe
mode, washer fluid will be dispensed onto the wind-
shield glass through the washer nozzles for as long
as the washer switch is held closed up to about thirty
seconds. When the Wash position is selected with the
wiper system operating in an intermittent wipe
mode, washer fluid is still dispensed until the control
knob is released; however, the 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 interval. If the control
knob is held in the depressed Wash position for more
than about thirty seconds, washer system operation
will be suspended until the control knob is released
for about two seconds then cycled back to the Wash
position.
²Wipe-After-Wash Mode- When the control
knob on the control stalk of the multi-function switch
is depressed to the momentary Wash position for
more than about one-half second with the wiper sys-
tem turned Off, the washer pump/motor and the wip-
ers will operate for as long as the washer switch is
held closed up to about thirty seconds, then provide
several additional wipe cycles after the control knob
DRWIPERS/WASHERS 8R - 3
WIPERS/WASHERS (Continued)

is released before parking the wiper blades near the
base of the windshield. If the control knob is held in
the depressed Wash position for more than about
thirty seconds, washer system operation will be sus-
pended until the control knob is released for about
two seconds then cycled back to the Wash position.
OPERATION
The wiper and washer system is designed to pro-
vide the vehicle operator with a convenient, safe, and
reliable means of maintaining visibility through the
windshield glass. The various components of this sys-
tem 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, or
other 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 wiper and washer
system functions with the control knob on the end of
the control stalk of the multi-function switch that
extends from the left 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 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. Depressing the control knob towards
the steering column actuates the momentary washer
system switch, which selects the Wash, Wipe-After-
Wash, and Pulse Wipe Modes depending upon when
and how long the switch is held closed. The multi-
function switch provides hard wired resistor multi-
plexed inputs to the instrument cluster for all of the
wiper and washer system functions. The instrument
cluster then sends electronic messages to the Front
Control Module (FCM) over the Programmable Com-
munications Interface (PCI) data bus requesting the
appropriate wiper and washer system operating
modes.
Wiper and washer system operation are completely
controlled by the instrument cluster and FCM logic
circuits, and that logic will only allow these systems
to operate when the ignition switch is in the Acces-
sory or On positions. Battery current is directed from
a B(+) fuse in the Integrated Power Module (IPM) to
the wiper on/off relay and the wiper high/low relay in
the IPM through a fused B(+) circuit. The FCM useslow side drivers to control wiper system operation by
energizing or de-energizing the wiper high/low and
wiper on/off relays. The FCM uses a high side driver
to control the operation of the washer pump motor
unit. The multi-function switch circuitry receives a
clean ground output from the instrument cluster on a
multi-function switch return circuit, then provides
resistor multiplexed inputs to the instrument cluster
on an intermittent wipe mux circuit to indicate the
selected wiper system mode and on a wash/beam
select mux circuit to indicate the selected washer sys-
tem mode.
The hard wired circuits and components of the
wiper and washer system may be diagnosed and
tested using conventional diagnostic tools and proce-
dures. However, conventional diagnostic methods
may not prove conclusive in the diagnosis of the
instrument cluster, the FCM, or the electronic mes-
sage inputs to or outputs from the instrument cluster
or FCM that control the wiper and washer system
operating modes. The most reliable, efficient, and
accurate means to diagnose the instrument cluster or
the FCM inputs and outputs related to the various
wiper and washer system operating modes requires
the use of a DRBIIItscan tool. Refer to the appro-
priate diagnostic information.
OPERATING MODES
Following are paragraphs that briefly describe the
operation of each of the wiper and washer system
operating modes.
CONTINUOUS WIPE MODE
When the Low position of the control knob on the
control stalk of the multi-function switch is selected
the instrument cluster sends an electronic wiper
switch low message to the FCM, then the FCM ener-
gizes the wiper on/off relay. This directs battery cur-
rent 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 wiper motor, causing the
wipers to cycle at low speed.
When the High position of the control knob is
selected the instrument cluster sends an electronic
wiper switch high message to the FCM, then the
FCM 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 speed
brush of the wiper motor, causing the wipers to cycle
at high speed.
When the Off position of the multi-function switch
control knob is selected, the instrument cluster sends
an electronic wiper switch off message to the FCM. If
8R - 4 WIPERS/WASHERSDR
WIPERS/WASHERS (Continued)

interval at which to de-energize the wiper on/off
relay to complete the wipe-after-wash mode cycle.
DIAGNOSIS AND TESTING - WIPER &
WASHER SYSTEM
If the wiper motor operates, but the wipers do not
move on the windshield, replace the faulty wiper
module. If the washer pump/motor operates, but no
washer fluid is dispensed on the glass; or, if the wip-
ers operate, but chatter, lift, or do not clear the glass,
clean and inspect the wiper and washer system com-
ponents as required. (Refer to 8 - ELECTRICAL/
WIPERS/WASHERS - CLEANING) and (Refer to 8 -
ELECTRICAL/WIPERS/WASHERS - INSPECTION).
For diagnosis and testing of the multi-function
switch (Refer to 8 - ELECTRICAL/LAMPS/LIGHT-
ING - EXTERIOR/MULTI-FUNCTION SWITCH -
DIAGNOSIS AND TESTING). Refer to the appropri-
ate 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 connec-
tors, splices and grounds.
The hard wired circuits and components of the
wiper and washer system may be diagnosed and
tested using conventional diagnostic tools and proce-
dures. However, conventional diagnostic methods
may not prove conclusive in the diagnosis of the
instrument cluster, the Front Control Module (FCM),
or the electronic message inputs to or outputs from
the instrument cluster and the FCM that control the
various wiper and washer system operating modes.
The most reliable, efficient, and accurate means to
diagnose the instrument cluster, the FCM, or the
electronic message inputs and outputs related to the
various wiper and washer system operating modes
requires the use of a DRBIIItscan tool. Refer to the
appropriate diagnostic information.
WARNING: TO AVOID PERSONAL INJURY OR
DEATH, ON VEHICLES EQUIPPED WITH AIRBAGS,
DISABLE THE SUPPLEMENTAL RESTRAINT SYS-
TEM BEFORE ATTEMPTING ANY STEERING
WHEEL, STEERING COLUMN, AIRBAG, SEAT BELT
TENSIONER, IMPACT SENSOR, OR INSTRUMENT
PANEL COMPONENT DIAGNOSIS OR SERVICE.
DISCONNECT AND ISOLATE THE BATTERY NEGA-
TIVE (GROUND) CABLE, THEN WAIT TWO MINUTES
FOR THE SYSTEM CAPACITOR TO DISCHARGE
BEFORE PERFORMING FURTHER DIAGNOSIS OR
SERVICE. THIS IS THE ONLY SURE WAY TO DIS-
ABLE THE SUPPLEMENTAL RESTRAINT SYSTEM.
FAILURE TO TAKE THE PROPER PRECAUTIONS
COULD RESULT IN ACCIDENTAL AIRBAG DEPLOY-
MENT.
CLEANING - WIPER & WASHER SYSTEM
WIPER SYSTEM
The squeegees of wiper blades exposed to the ele-
ments for a long time tend to lose their wiping effec-
tiveness. Periodic cleaning of the squeegees is
suggested to remove any deposits of salt or road film.
The wiper blades, arms, and windshield glass should
only be cleaned using a sponge or soft cloth and
windshield washer fluid, a mild detergent, or a non-
abrasive cleaner. If the wiper blades continue to
leave streaks, smears, hazing, or beading on the
glass after thorough cleaning of the squeegees and
the glass, the entire wiper blade assembly must be
replaced.
CAUTION: Protect the rubber squeegees of the
wiper blades from any petroleum-based cleaners,
solvents, or contaminants. These products can rap-
idly deteriorate the rubber squeegees.
WASHER SYSTEM
If the washer system is contaminated with foreign
material, drain the washer reservoir by removing the
washer pump/motor from the reservoir. Clean foreign
material from the inside of the washer pump/motor
inlet filter screen and the washer reservoir using
clean washer fluid, a mild detergent, or a non-abra-
sive cleaner. Flush foreign material from the washer
system plumbing by first disconnecting the washer
hoses from the washer nozzles, then running the
washer pump/motor to run clean washer fluid or
water through the system. Plugged or restricted
washer nozzles should be carefully back-flushed
using compressed air. If the washer nozzle obstruc-
tion cannot be cleared, replace the washer nozzle.
CAUTION: Never introduce petroleum-based clean-
ers, solvents, or contaminants into the washer sys-
tem. These products can rapidly deteriorate the
rubber seals and hoses of the washer system, as
well as the rubber squeegees of the wiper blades.
CAUTION: Never use compressed air to flush the
washer system plumbing. Compressed air pres-
sures are too great for the washer system plumbing
components and will result in further system dam-
age. Never use sharp instruments to clear a
plugged washer nozzle or damage to the nozzle ori-
fice and improper nozzle spray patterns will result.
8R - 6 WIPERS/WASHERSDR
WIPERS/WASHERS (Continued)