1998 DODGE RAM 1500 Headlamp unit

centerline. The side-to-side outboard edge of high
intensity pattern should be from 150 mm (6 in.) left
to 150 mm (6 in.) right of headlamp centerline (Fig.
12).The preferred headlamp alignment is 1(
down for the up/down adjustment and 0 for the
left/right adjustment.The high beam pattern
should be correct when the low beams are aligned
properly.
To adjust low beam headlamp, rotate vertical align-
ment screw to achieve the specified aim.
LICENSE PLATE LAMP
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Grasp license plate bulb socket and 1/4 turn
left to release from the license plate lamp unit.
(3) Pull bulb from license plate lamp socket.
INSTALLATION
(1) Install the bulb in the socket.
(2) Install the socket in to the license plate lamp
unit and 1/4 turn to lock.
(3) Connect the battery negative cable.
LICENSE PLATE LAMP UNIT
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Disconnect the harness connector.
(3) Remove the retaining clip. (Fig. 13).
(4) Separate license plate lamp from vehicle.
INSTALLATION
(1) Position license plate lamp on the bumper.
(2) Install the clip.
(3) Reconnect the harness connector.
(4) Connect the battery negative cable.
MARKER LAMP UNIT
REMOVAL
REMOVAL - FENDER MARKER LAMP
(1) Grasp the lens assembly firmly and push it
rearward to remove the lens assembly from the
fender (Fig. 14).
(2) Turn the bulb socket counterclockwise a quar-
ter turn and remove the bulb socket from the lens
assembly.
Fig. 13 License Plate Lamp Panel
1 - REAR BUMPER
2 - WIRING CONNECTOR
3 - CLIP
4 - LICENSE PLATE LAMP UNIT
Fig. 14 Fender Extension And Marker Lamp
Assembly
1 - WIRING HARNESS AND BULB SOCKET
2 - MARKER LAMP LENS ASSEMBLY
DRLAMPS/LIGHTING - EXTERIOR 8L - 17
HEADLAMP UNIT (Continued)

REMOVAL - TAILGATE MARKER LAMP
(1) Remove the two screws that secure the lens
assembly to the tailgate (Fig. 15).
(2) Turn the bulb sockets counterclockwise a quar-
ter turn and remove the bulb sockets from the lens
assembly.
INSTALLATION
INSTALLATION - FENDER MARKER LAMP
(1) Install the bulb socket to the lens assembly.
Turn the bulb socket a quarter turn clockwise.
(2) Position the lens assembly against the fender.
Using firm pressure, push the lens assembly into the
fender.
INSTALLATION - TAILGATE MARKER LAMP
(1) Install the bulb sockets into the lens assembly.
Turn the bulb sockets a quarter turn clockwise.(2) Position the lens assembly to the tailgate.
Install and tighten the two screws securely.
MULTI-FUNCTION SWITCH
DESCRIPTION - TURN SIGNAL SYSTEM
The multi-function switch is a resistive MUX
switch that is monitored by the Instrument Cluster.
The turn signals are actuated with the lever on
Multi-Function Switch. The signals are automatically
turned off by a canceling cam (two lobes molded to
the back of the clock spring mechanism). The cam
comes in contact with the cancel actuator on the turn
signal (multi-function) switch assembly. Either cam
lobe, pushing on the cancel actuator, returns the
switch to the OFF position.
OPERATION - TURN SIGNAL SYSTEM
The Instrument Cluster monitors the multiplexed
multifunction switch. In a turning event the Instru-
ment Cluster senses a change in the turn signal
lever and illuminates the appropriate turn signal
indicator. At the same time, the Instrument Cluster
will send a J1850 message on the PCI bus to the
Front Control Module (FCM). The FCM will respond
by activating the appropriate relay in the Power Dis-
tribution Center.
A chime will sound after the turn is completed if
vehicle has traveled a distance of approximately 1.0
mile and a speed of 15 mph, with the turn signal ON.
DIAGNOSIS AND TESTING - MULTI-FUNCTION
SWITCH
To test the turn signal, headlamp beam select and
optical horn portion of the multi-function switch:
(1) Remove the multi-function switch, refer to
Electrical, Lamps/Lighting - Exterior, Multi-Function
Switch, Removal, and Installation.
(2) Using an ohmmeter check the resistance read-
ings between multi-function switch pins. Refer to
Wiring Diagrams for proper pin numbers and the
MULTI-FUNCTION SWITCH TESTS table.
MULTI-FUNCTION SWITCH TESTS
EXTERIOR LIGHTING FUNCTIONS
SWITCH POSITION CONNECTOR PINS RESISTANCE (OHMS)
Off 1 - 2 Open
Headlamp High Beams On 1 - 2 518 - 575
Hazard 3 - 2 115 - 128
Fig. 15 Tailgate Marker Lamp Housing
1 - RETAINING NUT (2)
2 - TAILGATE
3 - WIRING HARNESS AND BULB SOCKET
4 - SCREW (2)
5 - LENS ASSEMBLY
8L - 18 LAMPS/LIGHTING - EXTERIORDR
MARKER LAMP UNIT (Continued)

PARK LAMP RELAY
DESCRIPTION
The park lamp relay is located in the Power Dis-
tribution Center (PDC) of the vehicle. The park lamp
relay is a conventional International Standards
Organization (ISO) micro relay (Fig. 17). Relays con-
forming to the ISO specifications have common phys-
ical dimensions, current capacities, terminal
patterns, and terminal functions.
The park lamp relay cannot be adjusted or
repaired and, if faulty or damaged, the unit must be
replaced.
OPERATION
The park lamp relay is an electromechanical
switch that uses a low current input from the Front
Control Module (FCM) to control a high current out-
put to the park lamps. 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 park lamp relay terminals are connected to
the vehicle electrical system through a connector in
the Junction Block (JB). The inputs and outputs of
the headlamp low beam relay include:
²Common Feed Terminal- The common feed
terminal (30) is connected to the park lamps through
the park lamp relay output circuit and provides
ground to the park lamps when the relay is de-ener-
gized, and battery current to the park lamps when-
ever the relay is energized.
²Coil Ground Terminal- The coil ground termi-
nal (85) is connected to a control output of the Front
Control Module (FCM) through a park lamp relay
control circuit. The FCM controls park lamp opera-
tion by controlling a ground path through this cir-
cuit.
²Coil Battery Terminal- The coil battery ter-
minal (86) receives battery current at all times from
a fuse in the PDC through a fused B(+) circuit.
²Normally Open Terminal- The normally open
terminal (87) receives battery current at all times
from a fuse in the Power Distribution Center (PDC)
through a fused B(+) circuit.
²Normally Closed Terminal- The normally
closed terminal (87A) is connected to ground at all
times.
The park lamp relay can be diagnosed using con-
ventional diagnostic tools and methods.
DIAGNOSIS AND TESTING - PARK LAMP
RELAY
The park lamp relay (Fig. 18) is located in the
Power Distribution Center (PDC). Refer to the appro-
priate wiring information.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE SUPPLEMENTAL RESTRAINT
SYSTEM BEFORE ATTEMPTING ANY STEERING
WHEEL, STEERING COLUMN, DRIVER AIRBAG,
PASSENGER AIRBAG, SEAT BELT TENSIONER,
FRONT IMPACT SENSORS, SIDE CURTAIN AIRBAG,
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) Remove the park lamp relay from the PDC.
(2) A relay in the de-energized position should
have continuity between terminals 87A and 30, and
Fig. 17 ISO Micro Relay
30 - COMMON FEED
85 - COIL GROUND
86 - COIL BATTERY
87 - NORMALLY OPEN
87A - NORMALLY CLOSED
8L - 20 LAMPS/LIGHTING - EXTERIORDR

no 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
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE SUPPLEMENTAL RESTRAINT
SYSTEM BEFORE ATTEMPTING ANY STEERING
WHEEL, STEERING COLUMN, DRIVER AIRBAG,
PASSENGER AIRBAG, SEAT BELT TENSIONER,
FRONT IMPACT SENSORS, SIDE CURTAIN AIRBAG,
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) Disconnect and isolate the battery negative
cable.(2) Remove the Power Distribution Center (PDC)
cover.
(3) Remove the park lamp relay by grasping it
firmly and pulling it straight out from the receptacle
in the PDC.
INSTALLATION
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE SUPPLEMENTAL RESTRAINT
SYSTEM BEFORE ATTEMPTING ANY STEERING
WHEEL, STEERING COLUMN, DRIVER AIRBAG,
PASSENGER AIRBAG, SEAT BELT TENSIONER,
FRONT IMPACT SENSORS, SIDE CURTAIN AIRBAG,
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) Position the park lamp relay to the proper
receptacle in the Power Distribution Center (PDC).
(2) Align the park lamp relay terminals with the
terminal cavities in the PDC.
(3) Press firmly and evenly on the top of the park
lamp relay until the terminals are fully seated in the
PDC.
(4) Install the PDC cover.
(5) Reconnect the battery negative cable.
PARK/TURN SIGNAL LAMP
REMOVAL
(1) Disconnect and isolate the negative battery
cable.
(2) Remove the headlamp unit.(Refer to 8 - ELEC-
TRICAL/LAMPS/LIGHTING - EXTERIOR/HEAD-
LAMP UNIT - REMOVAL).
(3) Remove the bulb socket from the headlamp
unit.
(4) Release the front park/turn signal bulb locking
tabs and remove the bulb from the socket (Fig. 19).
INSTALLATION
(1) Install the front park/turn signal bulb into the
bulb socket.
(2) Install the bulb socket into the headlamp unit.
(3) Install the headlamp unit (Refer to 8 - ELEC-
TRICAL/LAMPS/LIGHTING - EXTERIOR/HEAD-
LAMP UNIT - INSTALLATION).
Fig. 18 ISO Micro Relay
30 - COMMON FEED
85 - COIL GROUND
86 - COIL BATTERY
87 - NORMALLY OPEN
87A - NORMALLY CLOSED
DRLAMPS/LIGHTING - EXTERIOR 8L - 21
PARK LAMP RELAY (Continued)

(2) Disconnect wire harness connector to power
mirror switch (Fig. 1).
(3) Using two jumper wires:
²Connect one to a 12 volt source
²Connect the other to a good body ground
²Refer to the Mirror Motor Test Chart for proper
wire connections at the switch connector
MIRROR MOTOR TEST CHART
12 VOLTS GROUND MIRROR REACTION
SWITCH CONNECTOR RIGHT LEFT
PIN 1 PIN 2 - UP
PIN 6 PIN 2 - LEFT
PIN 2 PIN 1 - DOWN
PIN 2 PIN 6 - RIGHT
PIN 7 PIN 2 UP -
PIN 4 PIN 2 LEFT -
PIN 2 PIN 7 DOWN -
PIN 2 PIN 4 RIGHT -
(4) If results shown in table are not obtained,
check for open or shorted circuit. Replace mirror
assembly as necessary.
AUTOMATIC DAY / NIGHT
MIRROR
DESCRIPTION
The automatic day/night mirror uses a thin layer
of electrochromic material between two pieces of con-
ductive glass to make up the face of the mirror.
When the mirror switch is in the On position, two
photocell sensors are used by the mirror circuitry to
monitor external light levels and adjust the reflec-
tance of the mirror.
OPERATION
The ambient photocell sensor is located on the for-
ward-facing (windshield side) of the rear view mirror
housing, and detects the ambient light levels outside
of the vehicle. The headlamp photocell sensor is
located inside the rear view mirror housing behind
the mirror glass and faces rearward, to detect the
level of the light being received at the rear window
side of the mirror. When the circuitry of the auto-
matic day/night mirror detects that the difference
between the two light levels is too great (the light
level received at the rear of the mirror is much
higher than that at the front of the mirror), it begins
to darken the mirror.
The automatic day/night mirror circuitry also mon-
itors the transmission using an input from the
backup lamp circuit. The mirror circuitry is pro-
grammed to automatically disable its self-dimming
feature whenever it senses that the transmission
backup lamp circuit is energized.
The automatic day/night mirror is a completely
self-contained unit and cannot be repaired. If faulty
or damaged, the entire mirror assembly must be
replaced.
DIAGNOSIS AND TESTING - AUTOMATIC DAY /
NIGHT MIRROR
For complete circuit diagrams, refer to the appro-
priate wiring information.
(1) Check the fuse in the Integrated Power Module
(IPM). If OK, go to Step 2. If not OK, repair the
shorted circuit or component as required and replace
the faulty fuse.
(2) Turn the ignition switch to the On position.
Check for battery voltage at the fuse in the IPM. If
OK, go to Step 3. If not OK, repair the open circuit to
the ignition switch as required.
(3) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Unplug the wire harness connector from the auto-
matic day/night mirror (Fig. 2). Connect the battery
negative cable. Turn the ignition switch to the On
position. Check for battery voltage at the fused igni-
tion switch output (run/start) circuit cavity of the
automatic day/night mirror wire harness connector. If
OK, go to Step 4. If not OK, repair the open circuit to
the IPM as required.
(4) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Check for continuity between the ground circuit cav-
ity of the automatic day/night mirror wire harness
connector and a good ground. There should be conti-
nuity. If OK, go to Step 5. If not OK, repair the cir-
cuit to ground as required.
Fig. 1 POWER MIRROR SWITCH CONNECTOR
DRPOWER MIRRORS 8N - 11
POWER MIRRORS (Continued)

(FCM) on a sensor return circuit and the washer
fluid switch sense input to the FCM. When the
switch closes, the FCM senses the ground on the
washer fluid switch sense circuit. The FCM is pro-
grammed to respond to this input by sending an elec-
tronic washer fluid indicator lamp-on message to the
instrument cluster over the Programmable Commu-
nications Interface (PCI) data bus. The instrument
cluster responds to this message by illuminating the
washer fluid indicator and by sounding an audible
chime tone warning.
The washer fluid level switch 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
instrument cluster, the FCM, or the electronic mes-
sage inputs to or outputs from the instrument cluster
and the FCM that control the operation of the
washer fluid visual and/or audible indicators. The
most reliable, efficient, and accurate means to diag-
nose the washer fluid level indicator, the instrument
cluster, the FCM, or the electronic message inputs
and outputs related to the washer fluid indicator
requires the use of a DRBIIItscan tool. Refer to the
appropriate diagnostic information.
REMOVAL
The washer fluid level switch can be removed from
the washer reservoir without removing the reservoir
from the vehicle.
(1) Unlatch and open the hood.
(2) Disconnect and isolate the battery negative
cable.
(3) Disconnect the washer hose from the barbed
outlet nipple of the washer pump/motor unit and
allow the washer fluid to drain into a clean container
for reuse.
(4) Disconnect the right (except diesel engine) or
left (diesel engine only) headlamp and dash wire har-
ness connector for the washer fluid level switch from
the switch connector receptacle (Fig. 7) or (Fig. 8).
NOTE: The pivoting float of the washer fluid level
switch must be in a horizontal position within the
reservoir in order to be removed. With the reservoir
empty and in an upright position, the pivoting float
will orient itself to the horizontal position when the
switch connector receptacle is pointed straight
upwards.
(5) Using a trim stick or another suitable wide
flat-bladed tool, gently pry the barbed nipple of the
washer fluid level switch out of the rubber grommet
seal on the reservoir sump. Care must be taken not
to damage the reservoir.
(6) Remove the washer fluid level switch from the
washer reservoir.(7) Remove the rubber grommet seal from the
washer fluid level switch mounting hole in the
washer reservoir and discard.
Fig. 7 Washer Fluid Level Switch Remove/Install -
Except Diesel Engine
1 - WASHER HOSE
2 - WASHER RESERVOIR
3 - WASHER FLUID LEVEL SWITCH
4 - WIRE HARNESS
5 - WASHER PUMP/MOTOR
Fig. 8 Washer Fluid Level Switch Remove/Install -
Diesel Engine
1 - WIRE HARNESS
2 - WASHER RESERVOIR
3 - WASHER PUMP/MOTOR
4 - WASHER HOSE
5 - WASHER FLUID LEVEL SWITCH
8R - 10 WIPERS/WASHERSDR
WASHER FLUID LEVEL SWITCH (Continued)

INSTALLATION
(1) Install a new rubber grommet seal into the
washer fluid level switch mounting hole in the
washer reservoir. Always use a new rubber grommet
seal on the reservoir.
(2) Insert the float of the washer fluid level switch
through the rubber grommet seal and into the
washer reservoir. The connector receptacle of the
washer fluid level switch should be pointed upward.
(3) Using hand pressure, press firmly and evenly
on the washer fluid level switch mounting flange
until the barbed nipple is fully seated in the rubber
grommet seal in the washer reservoir mounting hole.
(4) Reconnect the right (except diesel engine) or
left (diesel engine only) headlamp and dash wire har-
ness connector for the washer fluid level switch to
the switch connector receptacle (Fig. 7) or (Fig. 8).
(5) Reconnect the removed washer hose to the
barbed outlet nipple of the washer pump/motor unit.
(6) Refill the washer reservoir with the washer
fluid drained from the reservoir during the removal
procedure.
(7) Reconnect the battery negative cable.
(8) Close and latch the hood.
WASHER HOSES/TUBES
DESCRIPTION
The washer plumbing consists of a small diameter
rubber reservoir washer hose that is routed from the
barbed outlet nipple of the electric washer pump/mo-tor unit on the washer reservoir through a trough
molded into the back of the reservoir above the
washer pump and to the engine compartment washer
hose (Fig. 9). On models equipped with an optional
diesel engine, the reservoir washer hose is routed
through routing clips on the top of the radiator fan
shroud from the washer reservoir on the left side of
the radiator to the engine compartment washer hose
on the right side of the radiator. The engine compart-
ment washer hose is contained within the right head-
lamp and dash wire harness, which is routed through
the engine compartment along the top of the right
front fender wheel house to the dash panel.
The engine compartment washer hose is connected
to the washer reservoir washer hose and to the cowl
plenum washer hose with molded plastic in-line fit-
tings that have a barbed nipple on each end. The
cowl plenum washer hose is routed from the engine
compartment into the cowl plenum area through a
trough formation located near the right end of the
cowl plenum cover/grille panel. The cowl plenum
washer hose is connected to the washer system check
valve/wye fitting on the underside of the cowl plenum
cover/grille panel. The cowl plenum washer hose and
the two washer nozzle hoses are routed through inte-
gral routing clips on the underside of the cowl ple-
num cover/grille panel. The cowl plenum washer hose
is connected to one nipple on the wye fitting and the
two washer nozzle hoses are connected to the other
two wye fitting nipples. The washer nozzle hoses are
then routed along the underside of the cowl plenum
cover/grille panel to the two washer nozzles.
Washer hose is available for service only as roll
stock, which must then be cut to length. The molded
plastic washer hose fittings cannot be repaired. If
these fittings are faulty or damaged, they must be
replaced.
OPERATION
Washer fluid in the washer reservoir is pressurized
and fed by the washer pump/motor through the
washer system plumbing and fittings to the two
washer nozzles. Whenever routing the washer hose
or a wire harness containing a washer hose, it must
be routed away from hot, sharp, or moving parts;
and, sharp bends that might pinch the hose must be
avoided.
WASHER NOZZLE
DESCRIPTION
The two washer nozzles have integral snap fea-
tures and an anti-rotation tab that secure them in
dedicated holes in the cowl plenum cover/grille panel
located near the base of the windshield (Fig. 10). The
Fig. 9 Engine Compartment Washer Hose
1 - RIGHT FENDER
2 - RIGHT HEADLAMP & DASH WIRE HARNESS
3 - ENGINE COMPARTMENT WASHER HOSE (TO COWL
PLENUM)
4 - COWL PLENUM WASHER HOSE
5 - ENGINE COMPARTMENT WASHER HOSE (TO WASHER
RESERVOIR)
DRWIPERS/WASHERS 8R - 11
WASHER FLUID LEVEL SWITCH (Continued)

(7) Reinstall both wiper arms onto the wiper piv-
ots. (Refer to 8 - ELECTRICAL/WIPERS/WASHERS/
WIPER ARM - INSTALLATION).
WASHER PUMP/MOTOR
DESCRIPTION
The washer pump/motor unit (Fig. 12) is located on
the rearward facing surface of the washer reservoir,
in the right (except diesel engine) or left (diesel
engine only) front corner of the engine compartment.
A small permanently lubricated and sealed electric
motor is coupled to the rotor-type washer pump. A
seal flange with a barbed inlet nipple on the pump
housing passes through a rubber grommet seal
installed in a dedicated mounting hole of the washer
reservoir. When the pump is installed in the reser-
voir a barbed outlet nipple on the pump housing con-
nects the unit to the washer system through a short
washer reservoir hose.
The washer pump/motor unit is retained on the
reservoir by the interference fit between the barbed
pump inlet nipple and the grommet seal, which is a
light press fit. The top of the washer pump is also
secured to the washer reservoir by the use of a snappost on the motor housing and a snap post receptacle
molded into the reservoir that allows for mounting of
the washer pump without the use of fasteners. An
integral connector receptacle on the top of the motor
housing connects the unit to the vehicle electrical
system. The washer pump/motor unit cannot be
repaired. If faulty or damaged, the entire washer
pump/motor unit must be replaced.
OPERATION
The washer pump/motor unit features a small
Direct Current (DC) electric motor. The motor is con-
nected to the vehicle electrical system through a sin-
gle take out and two-cavity connector of the right
(except diesel engine) or left (diesel engine only)
headlamp and dash wire harness. The motor is
grounded at all times through another take out of
the right (except diesel engine) or left (diesel engine
only) headlamp and dash wire harness. On models
without the diesel engine, a single eyelet terminal
connector is secured by a nut to a ground stud
located on the right front fender inner shield in the
engine compartment. On models with a diesel engine,
an eyelet terminal connector is secured by a ground
screw to the left front fender inner shield in the
engine compartment. The motor receives battery cur-
rent on a washer pump/motor control circuit.
The washer pump/motor control circuit is energized
through a high side driver within the Front Control
Module (FCM) whenever the FCM receives an elec-
tronic message requesting washer system operation
from the instrument cluster over the Programmable
Communications Interface (PCI) data bus. The
instrument cluster monitors a resistor multiplexed
hard wired input from the momentary washer switch
contacts within the multi-function switch on the
steering column to determine when it should issue
the electronic message requesting washer system
operation.
Washer fluid is gravity-fed from the washer reser-
voir to the inlet side of the washer pump. When the
pump motor is energized, the motor spins the rotor
within the washer pump. The spinning pump rotor
pressurizes the washer fluid and forces it through
the pump outlet nipple, the washer plumbing, and
the washer nozzles onto the windshield glass.
The washer pump/motor unit may be diagnosed
using conventional diagnostic tools and methods.
However, conventional diagnostic methods may not
prove conclusive in the diagnosis of the instrument
cluster, the FCM, or the electronic message inputs to
or outputs from the instrument cluster and the FCM
that control the operation of the washer pump/motor
unit. The most reliable, efficient, and accurate means
to diagnose the washer pump/motor unit, the instru-
ment cluster, the FCM, or the electronic message
Fig. 12 Washer Pump/Motor
1 - MOTOR
2 - SNAP POST
3 - CONNECTOR RECEPTACLE
4 - PUMP
5 - OUTLET NIPPLE
6 - INLET NIPPLE
7 - FILTER SCREEN
DRWIPERS/WASHERS 8R - 13
WASHER NOZZLE (Continued)