
nector for the multi-function switch. There should be
continuity. If OK, go to Step 11. If not OK, repair the
open hazard switch sense circuit between the multi-
function switch and the combination flasher.
(11) Check for continuity between the turn switch
sense circuit of the instrument panel wire harness
connector for the multi-function switch and a good
ground. There should be no continuity. If OK, go to
Step 12. If not OK, repair the shorted left turn
switch sense circuit between the multi-function
switch and the combination flasher.
(12) Check for continuity between the left turn
switch sense circuit of the JB for the combination
flasher and the instrument panel wire harness con-
nector for the multi-function switch. There should be
continuity. If OK, go to Step 13. If not OK, repair the
open left turn switch sense circuit between the multi-
function switch and the combination flasher.
(13) Check for continuity between the right turn
switch sense circuit of the instrument panel wire
harness connector for the left multi-function switch
and a good ground. There should be no continuity. If
OK, go to Step 14. If not OK, repair the shorted right
turn switch sense circuit between the left multi-func-
tion switch and the combination flasher.
(14) Check for continuity between the right turn
switch sense circuit of the JB for the combination
flasher and the instrument panel wire harness con-
nector for the multi-function switch. There should be
continuity. If OK, test the left multi-function switch.
(Refer to 8 - ELECTRICAL/LAMPS/LIGHTING -
EXTERIOR/LEFT MULTI-FUNCTION SWITCH -
DIAGNOSIS AND TESTING). If not OK, repair the
open right turn switch sense circuit between the
multi-function switch and the combination flasher as
required.
SPECIFICATIONS
EXTERIOR LAMPS
CAUTION: Do not use bulbs other than the bulbs
listed in the Bulb Application Table. Damage to
lamp can result. Do not touch halogen bulbs with
fingers or other oily surfaces. Bulb life will be
reduced.
LAMP BULB TYPE
BACK-UP 3157
CENTER HIGH
MOUNTED STOP LAMP921
FOG LAMP 9005
FRONT SIDE MARKER 194/194NA
LAMP BULB TYPE
FRONT TURN SIGNAL 3157/3157NA
HIGH BEAM 9005XS
LOW BEAM 9006XS
LICENSE PLATE 168
TAIL/BRAKE 3157
REAR TURN SIGNAL 3157
UNDERHOOD LAMP 561
AUTO HEADLAMP SENSOR
DIAGNOSIS AND TESTING - AUTO HEADLAMP
SENSOR (AHL)
The auto headlamp sensor needs real sunlight to
properly register the light level. When auto head-
lamps are enabled indoors, the headlamps may be
turned on. The sensor is located in the center of the
defroster grille at the base of the windshield. There
are no faults set in the Body Control Module (BCM)
for a inoperative or missing AHL Sensor. Symptom of
a missing sensor or unconnected sensor would be
that the Headlamps and Parklamps turn on when
the vehicle is started and there is a high level of
ambient light present (ie. daytime). Auto headlamps
should not function in the presence of daylight.
REMOVAL
(1) Remove the instrument panel top cover. (Refer
to 23 - BODY/INSTRUMENT PANEL/INSTRUMENT
PANEL TOP COVER - REMOVAL) for service proce-
dures.
(2) Remove the screw attaching auto headlamp
sensor to instrument panel (Fig. 1).
(3) Disengage the harness connector from auto
headlamp sensor.
(4) Separate the auto headlamp sensor from
instrument panel.
INSTALLATION
(1) Position the auto headlamp sensor on instru-
ment panel.
(2) Engage the harness connector to auto head-
lamp sensor.
(3) Install the screw attaching auto headlamp sen-
sor to instrument panel.
(4) Install the instrument panel top cover. (Refer
to 23 - BODY/INSTRUMENT PANEL/INSTRUMENT
PANEL TOP COVER - INSTALLATION) for service
procedures.
8L - 4 LAMPS/LIGHTING - EXTERIORWJ
LAMPS/LIGHTING - EXTERIOR (Continued)

AMBIENT TEMP SENSOR
DESCRIPTION
Ambient air temperature is monitored by the Elec-
tronic Vehicle Information Center (EVIC) through
ambient temperature messages received from the
Body Control Module (BCM) over the Programmable
Communications Interface (PCI) data bus network.
The BCM receives a hard wired input from the ambi-
ent temperature sensor. The ambient temperature
sensor is a variable resistor mounted to a bracket
that is secured with a screw to the right side of the
headlamp mounting module grille opening, behind
the radiator grille and in front of the engine compart-
ment.
Refer toBody Control Modulein Electronic Con-
trol Modules. For complete circuit diagrams, refer to
the appropriate wiring information. The ambient
temperature sensor cannot be adjusted or repaired
and, if faulty or damaged, it must be replaced.
OPERATION
The ambient temperature sensor is a variable
resistor that operates on a five-volt reference signal
sent to it by the BCM. The resistance in the sensor
changes as temperature changes, changing the tem-
perature sensor signal circuit voltage to the BCM.
Based upon the resistance in the sensor, the BCM
senses a specific voltage on the temperature sensor
signal circuit, which it is programmed to correspond
to a specific temperature. The BCM then sends the
proper ambient temperature messages to the EVIC
over the PCI data bus.
The temperature function is supported by the
ambient temperature sensor, a wiring circuit, the
Body Control Module (BCM), the Programmable
Communications Interface (PCI) data bus, and a por-
tion of the Electronic Vehicle Information Center
(EVIC) module. If any portion of the ambient temper-
ature sensor circuit fails, the BCM will self-diagnose
the circuit. A temperature reading of 130É F will
appear in the EVIC display in place of the tempera-
ture when the sensor circuit is shorted. A tempera-
ture reading of ±40É F will appear in the EVIC
display in place of the temperature when the sensor
circuit is open.
The ambient temperature sensor circuit can also be
diagnosed by referring toDiagnosis and Testing -
Ambient Temperature Sensor, and Diagnosis
and Testing - Ambient Temperature Sensor Cir-
cuit. If the temperature sensor and circuit are con-
firmed to be OK, but the temperature display is
inoperative or incorrect, refer toDiagnosis and
Testing - Electronic Vehicle Information Center
in this group. For complete circuit diagrams, refer to
the appropriate wiring information.
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - AMBIENT
TEMPERATURE SENSOR
(1) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Disconnect the ambient temperature sensor wire har-
ness connector.
(2) Measure the resistance of the ambient temper-
ature sensor. At ±40É C (±40É F), the sensor resis-
tance is 336.6 kilohms. At 60É C (140É F), the sensor
resistance is 2.49 kilohms. The sensor resistance
should read between these two values. If OK, refer to
Diagnosis and Testing - Ambient Temperature
Sensor Circuitin this group. If not OK, replace the
faulty ambient temperature sensor.
DIAGNOSIS AND TESTING - AMBIENT
TEMPERATURE SENSOR CIRCUIT
(1) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Disconnect the 2-way ambient temperature sensor
wire harness connector and the 22-way Body Control
Module (BCM) wire harness connector.
(2) Connect a jumper wire between the two termi-
nals in the body half of the 2-way ambient tempera-
ture sensor wire harness connector.
(3) Check for continuity between the sensor return
circuit and the ambient temperature sensor signal
circuit cavities of the 22-way BCM wire harness con-
nector. There should be continuity. If OK, go to Step
4. If not OK, repair the open sensor return circuit or
ambient temperature sensor signal circuit to the
ambient temperature sensor as required.
(4) Remove the jumper wire from the body half of
the 2-way ambient temperature sensor wire harness
connector. Check for continuity between the sensor
return circuit cavity of the 22-way BCM wire harness
connector and a good ground. There should be no
continuity. If OK, go to Step 5. If not OK, repair the
shorted sensor return circuit as required.
(5) Check for continuity between the ambient tem-
perature sensor signal circuit cavity of the 22-way
BCM wire harness connector and a good ground.
There should be no continuity. If OK, refer toDiag-
nosis and Testing - Electronic Vehicle Informa-
tion Centerin this group. If not OK, repair the
shorted ambient temperature sensor signal circuit as
required.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
8M - 12 MESSAGE SYSTEMSWJ

(2) Locate the ambient temperature sensor, on the
right side of the radiator opening in the headlamp
mounting module, behind the grille (Fig. 6).(3) Remove the radiator grille fascia and insert
from the headlamp mounting module. Refer to Body
for the procedures.
(4) Disconnect the wire harness connector from the
ambient temperature sensor connector receptacle.
(5) Remove the one screw that secures the ambient
temperature sensor bracket to the headlamp mount-
ing module.
(6) Remove the ambient temperature sensor from
the headlamp mounting module.
INSTALLATION
(1) Position the ambient temperature sensor onto
the headlamp mounting module.
(2) Install and tighten the one screw that secures
the ambient temperature sensor bracket to the head-
lamp mounting module. Tighten the screw to 2.2 N´m
(20 in. lbs.).
(3) Reconnect the wire harness connector to the
ambient temperature sensor connector receptacle.
(4) Install the radiator grille fascia and insert onto
the headlamp mounting module. Refer to the Body
section of this manual for the procedures.
(5) Reconnect the battery negative cable.
Fig. 6 AMBIENT TEMPERATURE SENSOR
1 - AMBIENT TEMPERATURE SENSOR
2 - WIRE HARNESS CONNECTOR
3 - HEADLAMP MOUNTING MODULE
WJMESSAGE SYSTEMS 8M - 13
AMBIENT TEMP SENSOR (Continued)

(4) Install airbag module. Refer to Group 8M, Pas-
sive Restraint Systems.
(5) Connect negative battery cable.
VACUUM RESERVOIR
DESCRIPTION
The vacuum reservoir is a plastic storage tank con-
nected to an engine vacuum source by vacuum lines.
OPERATION
The vacuum reservoir is used to supply the vac-
uum needed to maintain proper speed control opera-
tion when engine vacuum drops, such as in climbing
a grade while driving. A one-way check valve is used
in the vacuum line between the reservoir and the
vacuum source. This check valve is used to trap
engine vacuum in the reservoir. On certain vehicle
applications, this reservoir is shared with the heat-
ing/air-conditioning system. The vacuum reservoir
cannot be repaired and must be replaced if faulty.
DIAGNOSIS AND TESTING - VACUUM
RESERVOIR
(1) Disconnect vacuum hose at speed control servo
and install a vacuum gauge into the disconnected
hose.
(2) Start engine and observe gauge at idle. Vac-
uum gauge should read at least ten inches of mer-
cury.
(3) If vacuum is less than ten inches of mercury,
determine source of leak. Check vacuum line to
engine for leaks. Also check actual engine intake
manifold vacuum. If manifold vacuum does not meet
this requirement, check for poor engine performance
and repair as necessary.
(4) If vacuum line to engine is not leaking, check
for leak at vacuum reservoir. To locate and gain
access to reservoir, refer to Vacuum Reservoir Remov-
al/Installation in this group. Disconnect vacuum line
at reservoir and connect a hand-operated vacuum
pump to reservoir fitting. Apply vacuum. Reservoir
vacuum should not bleed off. If vacuum is being lost,
replace reservoir.
(5) Verify operation of one-way check valve and
check it for leaks.
(a) Locate one-way check valve. The valve is
located in vacuum line between vacuum reservoir
and engine vacuum source. Disconnect vacuum
hoses (lines) at each end of valve.
(b) Connect a hand-operated vacuum pump to
reservoir end of check valve. Apply vacuum. Vac-
uum should not bleed off. If vacuum is being lost,
replace one-way check valve.
(c) Connect a hand-operated vacuum pump to
vacuum source end of check valve. Apply vacuum.
Vacuum should flow through valve. If vacuum is
not flowing, replace one-way check valve. Seal the
fitting at opposite end of valve with a finger and
apply vacuum. If vacuum will not hold, diaphragm
within check valve has ruptured. Replace valve.
REMOVAL
The vacuum reservoir is located in the right/front
corner of the vehicle behind the front bumper fascia
(Fig. 8).
(1) Remove front bumper and grill assembly.
(2) Remove 1 support bolt near front of reservoir
(Fig. 8).
(3) Remove 2 reservoir mounting bolts.
(4) Remove reservoir from vehicle to gain access to
vacuum hose (Fig. 9). Disconnect vacuum hose from
reservoir fitting at rear of reservoir.
Fig. 7 Speed Control Switches
1 - MOUNTING SCREW
2 - SPEED CONTROL SWITCHES
8P - 8 SPEED CONTROLWJ
SWITCH (Continued)

INSTALLATION
The vacuum reservoir is located in the right/front
corner of the vehicle behind the front bumper fascia
(Fig. 8).
(1) Connect vacuum hose to reservoir.
(2) Install reservoir and tighten 2 bolts to 3 N´m
(25 in. lbs.) torque.
(3) Install front bumper and grill assembly.
Fig. 8 Vacuum Reservoir Location
1 - RADIATOR FAN RELAY
2 - VACUUM RESERVOIR
3 - BOLT
4 - RIGHT FRONT FENDER
Fig. 9 Vacuum Reservoir Removal/Installation
1 - VACUUM HOSE
2 - RADIATOR
3 - VACUUM RESERVOIR
WJSPEED CONTROL 8P - 9
VACUUM RESERVOIR (Continued)

²Front Check Valve- The front washer system
check valve is integral to the wye fitting located in
the washer plumbing between the cowl plenum
washer hose and the front washer nozzles, and is
concealed beneath the cowl plenum cover/grille panel
at the base of the windshield.
²Front Washer Nozzle- Two fluidic front
washer nozzles are secured with integral snap fea-
tures to dedicated openings in the cowl plenum cover/
grille panel located near the base of the windshield.
²Front Washer Plumbing- The plumbing for
the front washer system consists of rubber hoses and
molded plastic fittings. The plumbing is routed along
the left side of the engine compartment from the
washer reservoir, and through the dash panel into
the cowl plenum to the front washer nozzle fittings
beneath the cowl plenum cover/grille panel.
²Front Washer Pump/Motor- The front washer
pump/motor unit is located in a dedicated hole on the
lower outboard side of the washer reservoir, behind
the inner fender liner ahead of the left front wheel.
The front washer pump is located ahead of and below
the rear washer pump.
²Front Wiper Arm- The two front wiper arms
are secured with nuts to the threaded studs on the
ends of the two wiper pivot shafts, which extend
through the cowl plenum cover/grille panel located
near the base of the windshield.
²Front Wiper Blade- The two front wiper
blades are secured to the two front wiper arms with
an integral latch, and are parked on the glass near
the bottom of the windshield when the front wiper
system is not in operation.
²Front Wiper Module- The front wiper pivot
shafts are the only visible components of the front
wiper module. The remainder of the module is con-
cealed within the cowl plenum beneath the cowl ple-
num cover/grille panel. The front wiper module
includes the module bracket, four rubber-isolated
wiper module mounts, the front wiper motor, the
wiper motor crank arm, the two wiper drive links,
and the two front wiper pivots.
²Rain Sensor Module- Models equipped with
the optional automatic wiper feature have a Rain
Sensor Module (RSM) located behind a trim cover on
a bracket bonded to the inside surface of the wind-
shield glass, just above the inside rear view mirror
mounting button.
²Right Multi-Function Switch- The right
(wiper) multi-function switch is secured to the right
side of the multi-function switch mounting housing
near the top of the steering column, just below the
steering wheel. Only the control stalk for the right
multi-function switch is visible, while the remainder
of the switch is concealed beneath the steering col-
umn shrouds. The right multi-function switch con-tains all of the switches and control circuitry for both
the front and rear wiper and washer systems.
²Washer Fluid Level Switch- The washer fluid
level switch is located in a dedicated hole near the
center of the forward surface of the washer reservoir,
behind the left front wheel house splash shield.
²Washer Reservoir- The washer reservoir is
concealed between the left inner fender shield and
the left outer fender panel, behind the inner fender
liner and ahead of the left front wheel. The washer
reservoir filler neck is the only visible portion of the
reservoir, and it is accessed from the left front corner
of the engine compartment.
²Wiper High-Low Relay- The wiper high-low
relay is an International Standards Organization
(ISO) micro relay located in the Power Distribution
Center (PDC) in the engine compartment near the
battery.
²Wiper On-Off Relay- The wiper on-off relay is
an International Standards Organization (ISO) micro
relay located in the Power Distribution Center (PDC)
in the engine compartment near the battery.
Hard wired circuitry connects the front wiper and
washer system components to the electrical system of
the vehicle. These hard wired circuits are integral to
several wire harnesses, which are routed throughout
the vehicle and retained by many different methods.
These circuits may be connected to each other, to the
vehicle electrical system and to the front wiper and
washer system components through the use of a com-
bination of soldered splices, splice block connectors,
and many different types of wire harness terminal
connectors and insulators. Refer to the appropriate
wiring information. The wiring information includes
wiring diagrams, proper wire and connector repair
procedures, further details on wire harness routing
and retention, as well as pin-out and location views
for the various wire harness connectors, splices and
grounds.
OPERATING MODES
The components of the front wiper and washer sys-
tem are designed to work in concert to provide the
following operating modes:
²Automatic Wiper- In models equipped with
the optional automatic wiper feature, the internal
circuitry of both the right (wiper) multi-function
switch, the rain sensor module, and the BCM work
in concert to provide an automatic wiper mode with
five sensitivity selections. The BCM tells the Rain
Sensor Module (RSM) when the automatic wiper
mode is selected and the manually selected sensitiv-
ity level, then the rain sensor module tells the BCM
each time enough water droplets have accumulated
within the wipe pattern on the windshield to require
front wiper operation. The BCM then automatically
WJFRONT WIPERS/WASHERS 8R - 3
FRONT WIPERS/WASHERS (Continued)

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/
FRONT WIPERS/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.
FRONT CHECK VALVE
DESCRIPTION
A front washer system check valve is standard
equipment on this model. The front check valve is
integral to the front washer nozzle plumbing wye fit-
ting located in the cowl plenum beneath the cowl ple-
num cover/grille panel near the base of the
windshield. The check valve consists of a molded
plastic body with a round center section. Three
barbed hose nipples are formed in a wye configura-
tion on the outside circumference of the center sec-
tion of the valve body. Within the check valve body, a
small check valve operated by a small coiled spring
restricts flow through the unit until the valve is
unseated by a predetermined inlet fluid pressure.
The front check valve cannot be adjusted or repaired
and, if faulty or damaged, it must be replaced.
OPERATION
The front check valve provides more than one func-
tion in this application. It serves as a wye connector
fitting between the cowl grille panel and washer noz-
zle sections of the front washer supply hose. It also
prevents washer fluid from draining out of the front
washer supply hoses back to the washer reservoir.
This drain-back would result in a lengthy delay from
when the front washer switch is actuated until
washer fluid was dispensed through the front washer
nozzles, because the front washer pump would have
to refill the front washer plumbing from the reservoir
to the nozzles. Finally, the front check valve prevents
washer fluid from siphoning through the front
washer nozzles after the front washer system is
turned Off. When the front washer pump pressurizes
and pumps washer fluid from the reservoir through
the front washer plumbing, the fluid pressure over-
rides the spring pressure applied to the check valve
and unseats the valve, allowing washer fluid to flow
toward the front washer nozzles. When the front
washer pump stops operating, spring pressure seats
the check valve and fluid flow in either direction
within the front washer plumbing is prevented.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the wiper arms from the wiper pivots.
(Refer to 8 - ELECTRICAL/FRONT WIPERS/WASH-
ERS/FRONT WIPER ARMS - REMOVAL).
(3) Open the hood and pull the hood to plenum
seal off of the forward flanges of the cowl grille cover
and the plenum panel.
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
WJFRONT WIPERS/WASHERS 8R - 9
FRONT WIPERS/WASHERS (Continued)

(4) Remove the six plastic nuts (2 short and 4
long) that secure the cowl grille cover to the studs on
the cowl top panel near the base of the windshield
(Fig. 3).
(5) Lift the left end of the cowl grille cover off of
the cowl plenum panel far enough to access the front
washer plumbing.
(6) Disconnect the engine compartment washer
hose from the cowl grille cover washer hose at the
plastic elbow connector.
(7) Remove the cowl grille cover from the cowl ple-
num and cowl top panels through the opening
between the hood and the base of the windshield.
(8) From the underside of the cowl grille cover, dis-
connect the washer hoses from the three barbed nip-
ples of the wye fitting/check valve unit.
(9) Remove the wye fitting/check valve unit from
the underside of the cowl grille cover.
INSTALLATION
(1) Position the wye fitting/check valve unit to the
underside of the cowl grille cover.
(2) From the underside of the cowl grille cover,
reconnect the three washer hoses to the barbed nip-
ples of the wye fitting/check valve unit.
(3) Reinstall the washer hoses for the front washer
nozzles into their routing clips on the underside of
the cowl grille cover.
(4) Position the cowl grille cover onto the cowl ple-
num and cowl top panels through the opening
between the hood and the base of the windshield
(Fig. 3).(5) Lift the left end of the cowl grille cover off of
the cowl plenum panel far enough to access the front
washer plumbing.
(6) Reconnect the cowl grille cover washer hose to
the engine compartment washer hose at the elbow
connector.
(7) Install the six plastic nuts that secure the cowl
grille cover to the studs on the cowl top panel near
the base of the windshield. These nuts are to be
installed by pushing them onto the studs in the fol-
lowing sequence:
(a) First, install the short nuts to the third stud
from the right, then the second stud from the left.
(b) Next, install the long nuts to the right out-
board stud, then the left outboard stud.
(c) Finally, install the two remaining long nuts
to the third stud from the left, then the second
stud from the right.
(8) Starting at the ends and working toward the
center, push the hood to plenum seal onto the for-
ward flanges of the cowl grille cover and the plenum
panel.
(9) Reinstall the wiper arms onto the wiper pivots.
(Refer to 8 - ELECTRICAL/FRONT WIPERS/WASH-
ERS/FRONT WIPER ARMS - INSTALLATION).
(10) Reconnect the battery negative cable.
FRONT WASHER HOSES/
TUBES
DESCRIPTION
The front washer plumbing consists of a small
diameter rubber hose that is routed from the barbed
outlet nipple of the front washer pump/motor on the
washer reservoir along the filler neck into the engine
compartment. In the engine compartment, a molded
plastic in-line fitting with barbed nipples joins the
washer hose to another section of hose that is routed
near the left headlamp and dash wire harness to the
cowl plenum area. The engine compartment washer
hose passes from the engine compartment into the
cowl plenum area through a dedicated hole with a
rubber grommet near the left end of the cowl plenum
panel. A molded plastic elbow fitting with barbed nip-
ples joins the engine compartment hose to the cowl
grille cover hose. The cowl grille cover washer hose is
routed through routing clips on the underside of the
cowl grille cover to a molded plastic wye fitting with
barbed nipples and an integral check valve. The cowl
grille cover hose is connected to one nipple on the
wye fitting and the two washer nozzle hoses are con-
nected to the other two wye fitting nipples. The
washer nozzle hoses are routed along the underside
of the cowl grille cover to the two washer nozzles.
Fig. 3 Cowl Grille Cover Remove/Install
1 - WASHER HOSE CONNECTION
2 - STUDS (6)
3 - COWL GRILLE COVER
4 - PLASTIC NUT (6)
8R - 10 FRONT WIPERS/WASHERSWJ
FRONT CHECK VALVE (Continued)