1998 DODGE RAM 1500 Electrical

The previous disengagement conditions are pro-
grammed for added safety.
Once the speed control has been disengaged,
depressing the ACCEL switch restores the vehicle to
the target speed that was stored in the PCM's RAM
(ECM for diesel).
NOTE: Depressing the OFF switch will erase the set
speed stored in the PCM's/ECM's RAM.
If, while the speed control is engaged, the driver
wishes to increase vehicle speed, the PCM(ECM for
diesel)is programmed for an acceleration feature.
With the ACCEL switch held closed, the vehicle
accelerates slowly to the desired speed. The new tar-
get speed is stored in the PCM's/ECM's RAM when
the ACCEL switch is released. The PCM/ECM also
has a9tap-up9feature in which vehicle speed
increases at a rate of approximately 2 mph for each
momentary switch activation of the ACCEL switch.
The PCM/ECM also provides a means to decelerate
without disengaging speed control. To decelerate from
an existing recorded target speed, depress and hold
the COAST switch until the desired speed is reached.
Then release the switch. The ON, OFF switch oper-
ates two components: the PCM's/ECM's ON, OFF
input, and the battery voltage to the brake switch.
REMOVAL
Depending on engine control computer (JTEC
having a 3±plug connector or 5.7L V-8 NGC hav-
ing a 4±plug connector), 2 types of switches are
used. Both types of switches are internally and
externally different. The switches used with the
NGC system have attached pigtail leads (Fig. 9).
The switch used with the JTEC system does not
have an attached pigtail lead.
(1) Remove switch mounting screw (Fig. 8). or
(Fig. 9)
(2) Pull switch from steering wheel.
(3) Unplug electrical connector from switch (Fig.
8), or, switch pigtail wire harness from steering
wheel wire harness (Fig. 9) and remove switch.
INSTALLATION
(1) Plug electrical connector into switch (Fig. 8), or
connect pigtail wire harness to steering wheel wire
harness (Fig. 9). Be sure wires are not pinched.
(2) Position switch to steering wheel.
(3) Install switch mounting screw and tighten.
Refer to torque specifications.
Fig. 8 SPEED CONTROL SWITCHES (EXCEPT 5.7L
V-8 ENGINE)
1 - ELECTRICAL CONNECTORS
2 - MOUNTING SCREWS
3 - RIGHT SWITCH
4 - LEFT SWITCH
Fig. 9 SPEED CONTROL SWITCHES (WITH 5.7L V-8
ENGINE)
1 - MOUNTING SCREWS
2 - RIGHT SWITCH
3 - LEFT SWITCH
4 - PIGTAIL LEADS
8P - 8 SPEED CONTROLDR
SWITCH (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)

INSPECTION - WIPER & WASHER SYSTEM
WIPER SYSTEM
The wiper blades and wiper arms should be
inspected periodically, not just when wiper perfor-
mance problems are experienced. This inspection
should include the following points:
(1) Inspect the wiper arms for any indications of
damage, or contamination. If the wiper arms are con-
taminated with any foreign material, clean them as
required. (Refer to 8 - ELECTRICAL/WIPERS/
WASHERS - CLEANING). If a wiper arm is damaged
or corrosion is evident, replace the wiper arm with a
new unit. Do not attempt to repair a wiper arm that
is damaged or corroded.
(2) Carefully lift the wiper blade off of the glass.
Note the action of the wiper arm hinge. The wiper
arm should pivot freely at the hinge, but with no lat-
eral looseness evident. If there is any binding evident
in the wiper arm hinge, or there is evident lateral
play in the wiper arm hinge, replace the wiper arm.
CAUTION: Do not allow the wiper arm to spring
back against the glass without the wiper blade in
place or the glass may be damaged.
(3) Once proper hinge action of the wiper arm is
confirmed, check the hinge for proper spring tension.
Remove the wiper blade from the wiper arm. Either
place a small postal scale between the blade end of
the wiper arm and the glass, or carefully lift the
blade end of the arm away from the glass using a
small fish scale. Compare the scale readings between
the right and left wiper arms. Replace a wiper arm if
it has comparatively lower spring tension, as evi-
denced by a lower scale reading.
(4) Inspect the wiper blades and squeegees for any
indications of damage, contamination, or rubber dete-
rioration (Fig. 2). If the wiper blades or squeegees
are contaminated with any foreign material, clean
them and the glass as required. (Refer to 8 - ELEC-
TRICAL/WIPERS/WASHERS - CLEANING). After
cleaning the wiper blade and the glass, if the wiper
blade still fails to clear the glass without smearing,
streaking, chattering, hazing, or beading, replace the
wiper blade. Also, if a wiper blade is damaged or the
squeegee rubber is damaged or deteriorated, replace
the wiper blade with a new unit. Do not attempt to
repair a wiper blade that is damaged.
WASHER SYSTEM
The washer system components should be
inspected periodically, not just when washer perfor-
mance problems are experienced. This inspection
should include the following points:(1) Check for ice or other foreign material in the
washer reservoir. If contaminated, clean and flush
the washer system. (Refer to 8 - ELECTRICAL/WIP-
ERS/WASHERS - CLEANING).
(2) Inspect the washer plumbing for pinched, leak-
ing, deteriorated, or incorrectly routed hoses and
damaged or disconnected hose fittings. Replace dam-
aged or deteriorated hoses and hose fittings. Leaking
washer hoses can sometimes be repaired by cutting
the hose at the leak and splicing it back together
using an in-line connector fitting. Similarly, sections
of deteriorated hose can be cut out and replaced by
splicing in new sections of hose using in-line connec-
tor fittings. Whenever routing a washer hose or a
wire harness containing a washer hose, it must be
routed away from hot, sharp, or moving parts. Also,
sharp bends that might pinch the washer hose must
be avoided.CHECK VALVE
DESCRIPTION
A single washer system check valve is standard
equipment on this model, and is installed in the
Fig. 2 Wiper Blade Inspection
1 - WORN OR UNEVEN EDGES
2 - ROAD FILM OR FOREIGN MATERIAL DEPOSITS
3 - HARD, BRITTLE, OR CRACKED
4 - DEFORMED OR FATIGUED
5 - SPLIT
6 - DAMAGED SUPPORT COMPONENTS
DRWIPERS/WASHERS 8R - 7
WIPERS/WASHERS (Continued)

washer system plumbing (Fig. 3). The check valve is
integral to the washer nozzle plumbing wye fitting
located in the cowl plenum area beneath the cowl
plenum cover/grille panel near the base of the wind-
shield. The check valve consists of a molded plastic
body with a raised arrowhead molded into its center
section that indicates the direction of the flow
through the valve, and three barbed hose nipples
formed in a wye configuration on the outside circum-
ference of the center section of the valve body. The
check valve cannot be adjusted or repaired and, if
faulty or damaged, it must be replaced.
OPERATION
The check valve provides more than one function
in this application. It serves as a wye connector fit-
ting between the engine compartment and washer
nozzle sections of the washer supply hose. It prevents
washer fluid from draining out of the washer supply
hoses back to the washer reservoir. This drain-back
would result in a lengthy delay from when the
washer switch is actuated until washer fluid was dis-
pensed through the washer nozzles, because the
washer pump would have to refill the washer plumb-
ing from the reservoir to the nozzles. Such a drain-
back condition could also result in water, dirt, or
other outside contaminants being siphoned into the
washer system through the washer nozzle orifice.
This water could subsequently freeze and plug the
nozzle, while other contaminants could interfere with
proper nozzle operation and cause improper nozzle
spray patterns. In addition, the check valve prevents
washer fluid from siphoning through the washer noz-
zles after the washer system is turned Off.When the washer pump pressurizes and pumps
washer fluid from the reservoir through the washer
plumbing, the fluid pressure unseats a diaphragm
from over a sump well within the valve by overriding
the spring pressure applied to it by a piston (Fig. 4).
With the diaphragm unseated, washer fluid is
allowed to flow toward the two washer nozzles. When
the washer pump stops operating, the spring pres-
sure on the piston seats the diaphragm over the
sump well in the valve and fluid flow in either direc-
tion within the washer plumbing is prevented. The
check valve cannot be adjusted or repaired and, if
faulty or damaged, it must be replaced.REMOVAL
(1) Remove both wiper arms from the wiper pivots.
(Refer to 8 - ELECTRICAL/WIPERS/WASHERS/
WIPER ARM - REMOVAL).
(2) Unlatch and open the hood.
(3) Remove the cowl plenum cover/grille panel
from over the cowl plenum. (Refer to 23 - BODY/EX-
TERIOR/COWL GRILLE - REMOVAL).
(4) From the underside of the cowl plenum cover/
grille panel, disconnect the cowl plenum and washer
nozzle hoses from the three barbed nipples of the
check valve (Fig. 5).
(5) Remove the check valve from the underside of
the cowl plenum cover/grille panel.
INSTALLATION
(1) Position the check valve to the underside of the
cowl plenum cover/grille panel (Fig. 5). Be certain
that the flow direction arrow molded into the check
valve body is oriented towards the washer nozzles.
Fig. 3 Check Valve
1 - INLET NIPPLE
2 - CHECK VALVE
3 - OUTLET NIPPLE (2)
4 - FLOW DIRECTION ARROW
Fig. 4 Check Valve
1 - SPRING
2 - PISTON
3 - DIAPHRAGM
4 - TO WASHER NOZZLE
5 - FROM WASHER PUMP
8R - 8 WIPERS/WASHERSDR
CHECK VALVE (Continued)