ECU CHRYSLER CARAVAN 2002 Manual PDF
[x] Cancel search | Manufacturer: CHRYSLER, Model Year: 2002, Model line: CARAVAN, Model: CHRYSLER CARAVAN 2002Pages: 2399, PDF Size: 57.96 MB
Page 464 of 2399
(2) Install and tighten the three screws that secure
the heated seat switch to the back of the instrument
panel center bezel. Tighten the screws to 1.5 N´m (13
in. lbs.) (Fig. 4).
(3) Install the center bezel onto the instrument
panel. Refer toInstrument Panel Center Bezelin
the Body section for the procedure.
(4) Reconnect the battery negative cable.
HEATED SEAT ELEMENT
DESCRIPTION
The heated seat system includes two seat heating ele-
ments in each front seat, one for the seat cushion and
the other for the seat back. The two elements for each
seat that are connected in series with the Heated Seat
Module (HSM). The temperature sensor is a Negative
Temperature Coefficient (NTC) thermistor. One temper-
ature sensor is used for each seat, and it is located on
the seat cushion heating element for all models.
The seat heating elements are sewn into the seat
cushion cover trim and seat back cover trim units.
The heated seat elements and the temperature sen-
sor cannot be adjusted or repaired and, if faulty or
damaged, the seat element assembly must be
replaced. Refer to the procedure in this section.
OPERATION
The heated seat elements resist the flow of electrical
current. When battery current is passed through the
elements, the energy lost by the resistance of the ele-
ments to the current flow is released in the form of
heat. The temperature sensor is a NTC thermistor.
When the temperature of the seat cushion cover rises,
the resistance of the sensor decreases. The heated seat
module supplies a five-volt current to one side of each
sensor, and monitors the voltage drop through the
sensor on a return circuit. The heated seat module
uses this temperature sensor input to monitor the
temperature of the seat, and regulates the current
flow to the seat heating elements accordingly.
DIAGNOSIS AND TESTING - HEATED SEAT
ELEMENTS
The wire harness connectors for the seat cushion and
seat back heating elements are located under the seat,
at the heated seat module. For circuit descriptions and
diagrams, refer to section 8W, Wiring Diagrams.
In order to access and test the heated seat ele-
ments it will be necessary to remove the appropriate
front seat retaining bolts and lay the seat rearward,
up against one of the rear seats. It is not necessary
to disconnect the seat electrical connectors, just use
care not to damage the attached wire harnesses
while testing.NOTE: WHEN CHECKING HEATED SEAT ELE-
MENTS FOR CONTINUITY, BE CERTAIN TO MOVE
THE HEATING ELEMENT BEING CHECKED. MOV-
ING THE ELEMENT, SUCH AS SITTING IN THE SEAT
WILL ELIMINATE THE POSSIBILITY OF AN INTER-
MITTENT OPEN IN THE ELEMENT WHICH WOULD
ONLY BE EVIDENT IF THE ELEMENT WAS MOVED
IN A CERTAIN DIRECTION. FAILURE TO CHECK
THE ELEMENT IN VARIOUS POSITIONS COULD
RESULT IN AN INCOMPLETE TEST.
SEAT CUSHION ELEMENT
(1) From under the vehicle, remove the appropri-
ate seats four retaining nuts.
(2) From inside the vehicle, pull the seat up, off
the mounting studs and lay it back, up against one of
the rear seats.
(3) Locate the heated seat module, attached to the
bottom of the seat cushion pan. Remove the heated
seat module from the seat cushion pan. Do not dis-
connect the electrical connectors at this time.
(4) Locate the green 4-way electrical connector,
connected to the heated seat module. Disconnect the
green 4-way connector from the heated seat module.
(5) Check for continuity between the two outboard
circuit cavities of the wire harness connector (Pins
1&4). There should be continuity. If OK, refer to
Heated Seat Module Diagnosis and Testing in the
Electronic Control Modules section of the service
manual for complete system testing procedures. If
not OK, install a replacement heated seat cushion
element. Refer to the procedure in this section.
SEAT BACK ELEMENT
(1) From under the vehicle, remove the appropri-
ate seats four retaining nuts.
(2) From inside the vehicle, pull the seat up and
off the mounting studs and lay it back, up against
one of the rear seats.
(3) Locate the heated seat module, attached to the
bottom of the seat cushion pan. Remove the heated
seat module from the seat cushion pan. Do not dis-
connect the electrical connectors at this time.
(4) Locate the gray 2-way electrical connector, con-
nected to the heated seat module. Disconnect the
2-way connector from the heated seat module.
(5) Check for continuity between the two circuit
cavities of the 2-way wire harness connector. There
should be continuity. If OK, refer to Heated Seat
Module Diagnosis and Testing in the Electronic Con-
trol Modules section of the service manual for com-
plete system testing procedures. If not OK, install a
replacement heated seat back element. Refer to the
procedure in this section.
RSHEATED SEAT SYSTEM8G-11
DRIVER HEATED SEAT SWITCH (Continued)
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REMOVAL
Do not remove the OEM heating element from the
seat or seat back cushion/trim covers. The original
element is permanently attached and cannot be
removed without permanent damage. The service
replacement heating element is designed to be
applied directly on the seat cushion.
(1) Disconnect and isolate the negative battery
cable.
(2) Remove the appropriate seat cushion or seat
back trim cover. Refer to the Body section of the ser-
vice manual for the procedures.
(3) Disconnect the inoperative heated seat cushion
or seat back element electrical connectors.
(4) Locate the wires leading from the inoperative
heating element and cut them off flush with the edge
of the original heating element.
INSTALLATION
(1) Peel off the adhesive backing on the back of the
replacement heating element and stick directly on
the foam cushion.
CAUTION: During the installation of the replace-
ment heating element, be careful not to fold or
crease the element assembly. Folds or creases will
cause premature failure.
(2) Connect the new heating element electrical
connectors (Fig. 5).
(3) Connect the negative battery cable.
(4) Verify heated seat system operation.
(5) Install the appropriate seat cushion or seat
back trim cover. Make certain the seat wire harness
is correctly routed through the seat and seat back.
The excess wire between the cushion and back ele-
ments should be securely tucked between the rear of
the cushion foam and the rear carpet flap of the trim
cover.
HEATED SEAT SENSOR
DESCRIPTION
Two heated seat sensors are used per vehicle, one
in each front seat cushion heating element. The
heated seat temperature sensor is a Negative Tem-
perature Coefficient (NTC) thermistor.
The heated seat sensors cannot be repaired or
adjusted and if found to be faulty, the complete
heated seat cushion element must be replaced.
OPERATION
The temperature sensor is a NTC thermistor.
When the temperature of the seat cushion cover
rises, the resistance of the sensor decreases. The
heated seat module supplies a five-volt current to one
side of each sensor, and monitors the voltage drop
through the sensor on a return circuit. The heated
seat module uses this temperature sensor input to
monitor the temperature of the seat, and regulates
the current flow to the seat heating elements accord-
ingly.
DIAGNOSIS AND TESTING - HEATED SEAT
SENSOR
For complete circuit diagrams, refer toWiring
Diagrams.
(1) Disconnect and isolate the battery negative
cable. Disconnect the green 4-way heated seat mod-
ule wire harness connector.
(2) Using an ohmmeter, check the resistance
between cavities 2 and 3. The sensor resistance
should be between 2 kilohms at 15É C (60É F) and 50
kilohms at 30É C (85É F). If not OK, replace the
faulty seat element and sensor assembly.
Fig. 5 HEATING ELEMENT INSTALLED - TYPICAL
1 - SEAT BACK WIRE HARNESS
2 - HEATED SEAT WIRE HARNESS CONNECTOR
3 - HEATED SEAT CUSHION ELEMENT
8G - 12 HEATED SEAT SYSTEMRS
HEATED SEAT ELEMENT (Continued)
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CHECKING SWITCH ONLY
(1) Disconnect and isolate the battery negative
cable. Remove the center bezel from the instrument
panel (Refer to 23 - BODY/INSTRUMENT PANEL/
INSTRUMENT PANEL CENTER BEZEL - REMOV-
AL). Check for continuity between the ground circuit
cavity (#10) of the instrument panel switch bank
electrical connector and a good ground. There should
be continuity. If OK, go to Step 2. If not OK, repair
the open ground circuit to ground as required.
(2) Reconnect the battery negative cable. Turn the
ignition switch to the On position. Check for battery
voltage at the fused ignition switch output (run) cir-
cuit cavity of the instrument panel switch bank con-
nector (#4). If OK, turn the ignition switch to the Off
position, and go to Step 3. If not OK, repair the open
fused ignition switch output (run) circuit as required.
(3) Test the heated seat switch as shown in the
Heated Seat Switch Test chart and the connector pin-
out below (Fig. 7). If OK, go to Step 4. If not OK,
replace the faulty switch bank assembly.
PASSENGER HEATED SEAT SWITCH TEST
SWITCH
POSITIONRESISTANCE
BETWEENRESISTANCE
(OHMS)
Off Pin3&4OPEN
Low Pin3&43570
High Pin3&41430
All resistance values are 1%.(4) Reconnect the instrument panel switch bank
and test the heated seat system for proper operation.
If the system is still inoperative proceed with check-
ing remaining components.
REMOVAL
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, REFER TO THE RESTRAINTS SECTION OF
THIS MANUAL BEFORE ATTEMPTING ANY STEER-
ING WHEEL, STEERING COLUMN, SEAT OR
INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the instrument panel center bezel.
Refer toInstrument Panel Center Bezelin the
Body section for the procedure.
(3) Remove the three screws (Fig. 8) that secure
the heated seat switch to the back of the instrument
panel center bezel.
(4) Remove the heated seat switch from the back
of the instrument panel center bezel.
Fig. 7 Instrument Panel Switch Bank Connector
Fig. 8 SWITCH RETAINING SCREWS
1 - HEATED SEAT SWITCH ASSEMBLY
2 - RETAINING SCREWS
8G - 14 HEATED SEAT SYSTEMRS
PASSENGER HEATED SEAT SWITCH (Continued)
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INSTALLATION
(1) Position the heated seat switch onto the back
of the instrument panel center bezel.
(2) Install and tighten the three screws that secure
the heated seat switch to the back of the instrument
panel center bezel. Tighten the screws to 1.5 N´m (13
in. lbs.) (Fig. 8).(3) Install the center bezel onto the instrument
panel. Refer toInstrument Panel Center Bezelin
the Body section for the procedure.
(4) Reconnect the battery negative cable.
RSHEATED SEAT SYSTEM8G-15
PASSENGER HEATED SEAT SWITCH (Continued)
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Page 484 of 2399
(3) On All Wheel Drive vehicles install the PTU
(Power Transfer Unit) for the rear wheels, refer to
the Transmission section for more information.
(4) Lower vehicle.
(5) Connect the negative cable.
SPARK PLUG
DESCRIPTION
DESCRIPTION - STANDARD 4 CYLINDER
All engines use resistor spark plugs. They have
resistance values ranging from 6,000 to 20,000 ohms
when checked with at least a 1000 volt spark plug
tester.
Do not use an ohm meter to check the resis-
tance of the spark plugs. This will give an inac-
curate reading.
Refer to the Specifications section for gap and type
of spark plug.
DESCRIPTION - PLATINUM PLUGS
The V6 engines use platinum resistor spark plugs.
They have resistance values of 6,000 to 20,000 ohms
when checked with at least a 1000 volt tester. Forspark plug identification and specifications, Refer to
the Specifications section.
Do not use an ohm meter to check the resis-
tance of the spark plugs. This will give an inac-
curate reading.
When the spark plugs use a single or double plat-
inum tips and they have a recommended service life
of 100,000 miles for normal driving conditions per
schedule A in this manual. The spark plugs have a
recommended service life of 75,000 miles for severe
driving conditions per schedule B in this manual. A
thin platinum pad is welded to both or center elec-
trode end(s) as show in (Fig. 13). Extreme care must
be used to prevent spark plug cross threading, mis-
gaping (Fig. 14) and ceramic insulator damage dur-
ing plug removal and installation.
CAUTION: Cleaning of the platinum plug may dam-
age the platinum tip.
REMOVAL
When replacing the spark plugs and spark plug
cables, route the cables correctly and secure them in
the appropriate retainers. Failure to route the cables
properly can cause the radio to reproduce ignition
noise, cross ignition of the spark plugs orshort cir-
cuit the cables to ground.
Always remove cables by grasping at the boot,
rotating the boot 1/2 turn, and pulling straight back
in a steady motion.
(1) Prior to removing the spark plug, spray com-
pressed air around the spark plug hole and the area
around the spark plug.
(2) Remove the spark plug using a quality socket
with a foam insert.
(3) Inspect the spark plug condition.
Fig. 12 Knock Sensor
1 - GENERATOR
2 - INTAKE MANIFOLD
3 - KNOCK SENSOR
4-STARTER
Fig. 13 Platinum Pads
1 - APPLY ANTI-SEIZE COMPOUND HERE ONLY
2 - PLATINUM SPARK SURFACE
RSIGNITION CONTROL8I-9
KNOCK SENSOR (Continued)
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INSTALLATION
When replacing the spark plugs and spark plug
cables, route the cables correctly and secure them in
the appropriate retainers. Failure to route the cables
properly can cause the radio to reproduce ignition
noise, cross ignition of the spark plugs orshort cir-
cuit the cables to ground.
(1) To avoid cross threading, start the spark plug
into the cylinder head by hand.
(2) Tighten spark plugs to 17.5 N´m (13 ft. lbs.)
torque.
(3) Install spark plug cables over spark plugs. A
click will be heard and felt when the cable properly
attaches to the spark plug.
SPARK PLUG CABLE
DESCRIPTION
Spark Plug cables are sometimes referred to as
secondary ignition wires. The wires transfer electri-
cal current from the ignition coil pack to individual
spark plugs at each cylinder. The resistive spark plug
cables are of nonmetallic construction. The cables
provide suppression of radio frequency emissions
from the ignition system.
Check the spark plug cable connections for good
contact at the coil, and spark plugs. Terminals should
be fully seated. The insulators should be in good con-
dition and should fit tightly on the coil, and spark
plugs. Spark plug cables with insulators that are
cracked or torn must be replaced.
Clean Spark Plug cables with a cloth moistened
with a non-flammable solvent. Wipe the cables dry.
Check for brittle or cracked insulation. The spark
plug cables and spark plug boots are made from high
temperature silicone materials. All spark plug cable
leads are properly identified with cylinder numbers.
The inside of most the spark plug boot is coated with
a special high temperature silicone grease for greater
sealing and to minimize boot bonding to the spark
plug insulator.
REMOVAL
Failure to route the cables properly could cause the
radio to reproduce ignition noise, cross ignition of the
spark plugs or short circuit the cables to ground.
Remove spark plug cable from coil first.
Always remove the spark plug cable by grasping
the top of the spark plug insulator, turning the boot
1/2 turn and pulling straight up in a steady motion.
INSTALLATION
Failure to route the cables properly could cause the
radio to reproduce ignition noise, cross ignition of the
spark plugs or short circuit the cables to ground.
Install spark plug insulators over spark plugs.
Ensure the top of the spark plug insulator covers the
upper end of the spark plug tube, then connect the
other end to coil pack.
Fig. 14 Setting Spark Plug Electrode Gap
1 - TAPER GAUGE
8I - 10 IGNITION CONTROLRS
SPARK PLUG (Continued)
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SPEEDOMETER DIAGNOSIS
CONDITION POSSIBLE CAUSES CORRECTION
NO POINTER
MOVEMENT.1. INTERNAL CLUSTER
FAILURE.1.A. PERFORM CLUSTER SELF-DIAGNOSTIC TEST
AND CHECK FOR FAULT CODES.
²IF SPEEDOMETER POINTER MOVES TO
CALIBRATION POINTS DURING TEST LOOK FOR
ANOTHER POSSIBLE CAUSE OF FAILURE.
²IF THE POINTER DOESN'T MOVE DURING TEST,
CHECK FOR POWER AND GROUND TO THE MIC. IF
POWER AND GROUND ARE PRESENT GO TO STEP
1.B.
1.B. REPLACE CLUSTER. GO TO STEP 1.C.
1.C. CONNECT CLUSTER INTO INSTRUMENT
PANEL WIRING HARNESS. PLACE IT BACK INTO
THE PROPER POSITION IN THE INSTRUMENT
PANEL. PUT IN THE TOP FOUR MOUNTING
SCREWS AND SECURE THE CLUSTER TO THE
INSTRUMENT PANEL.
2. NO SPEED PCI BUS
MESSAGE OR ZERO
MPH PCI SPEED BUS
MESSAGE.2.A. CHECK THE PCM (CODE 10) USING A DRB IIIT
SCAN TOOL. IF OK, GO TO STEP 2.B. IF NOT OK,
REFER TO THE PROPER POWERTRAIN
DIAGNOSTIC PROCEDURES MANUAL TO REPAIR
THE PCM.
2.B. CHECK THE SPEED SIGNAL INPUT INTO THE
PCM. THE SPEED SIGNAL ORIGINATES FROM ONE
OF THE FOLLOWING SOURCES:
²A DISTANCE SENSOR FOR VEHICLES WITH 3
SPEED AUTOMATIC TRANSMISSION. CHECK
CONTINUITY FROM DISTANCE SENSOR TO PCM. IF
OK, REPLACE DISTANCE SENSOR. IF NOT OK,
REPAIR WIRING.
²THE TCM FOR VEHICLES WITH THE 4 SPEED
ELECTRONIC TRANSMISSIONS. CHECK
CONTINUITY FROM TCM TO PCM. IF OK, USE A
DRB IIITSCAN TOOL TO CHECK TCM. REFER TO
THE PROPER TRANSMISSION DIAGNOSTIC
PROCEDURES MANUAL TO REPAIR THE TCM. IF
NOT OK, REPAIR WIRING.
8J - 4 INSTRUMENT CLUSTERRS
INSTRUMENT CLUSTER (Continued)
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CONDITION POSSIBLE CAUSES CORRECTION
ALL SEGMENTS ARE ON. 1. NO PCI BUS
MESSAGE FROM THE
TCM.1.A. PERFORM CLUSTER SELF-DIAGNOSTIC TEST.
IF PRND3L (PRND1234 IF AUTOSTICK EQUIPPED)
PASSES TEST GO TO STEP 1.B. IF PRND3L
(PRND1234 IF AUTOSTICK EQUIPPED) FAILS TEST,
REPLACE CLUSTER ASSEMBLY.
1.B. CHECK THE TCM USING A DRB IIITSCAN
TOOL. REFER TO THE PROPER TRANSMISSION
DIAGNOSTIC PROCEDURES MANUAL TO
PROPERLY DIAGNOSE AND REPAIR.
MECHANICAL TRANSMISSION RANGE INDICATOR (PRND21) DIAGNOSIS
CONDITION POSSIBLE CAUSES CORRECTION
INDICATOR DOES NOT
SHOW PROPER GEAR
OR NO INDICATION.MIS-ADJUSTED. 1.A. VERIFY TRANSMISSION SHIFT SYSTEM IS
CORRECTLY ADJUSTED.
1.B. VERIFY CORRECT ROUTING AND
ATTACHMENT OF PRNDL CABLE AND GUIDE TUBE.
1.C. RE-ADJUST PRNDL INDICATOR IN NEUTRAL
USING ADJUSTER WHEEL BELOW STEERING
COLUMN.
INDICATOR DOES NOT
FOLLOW GEAR SHIFT
LEVER.NOT ATTACHED. 1.A. VERIFY INDICATOR CABLE CONNECTED TO
SHIFT LEVER PIN IN THE GROOVE.
1.B. VERIFY THAT THE INDICATOR CLIP IS SECURE,
AND ATTACHED TO THE MOUNTING BRACKET.
MAKE SURE THAT THE CLIP IS NOT BROKEN. IF
THE CLIP IS BROKEN, REPLACE CLIP ON
INDICATOR.
INDICATOR DOES NOT
MAKE FULL TRAVEL (ªPº
< > ª1º).1. CABLE DISLODGED
FROM ITS PATH ON THE
INDICATOR BASE.1. VERIFY CORRECT ATTACHMENT OF INDICATOR
CABLE TO SHIFT LEVER PIN (UNDER HOOP OF
TRANS. SHIFT CABLE) AND CLIP ONTO THE
MOUNTING BRACKET.
2. INCORRECT
ATTACHMENT OF CABLE
TO SHIFT LEVER PIN.2. VERIFY INDICATOR TRAVEL BY PULLING ON
CABLE GENTLY OVER FULL TRAVEL RANGE. IF
THERE IS STILL A PROBLEM, REMOVE CLUSTER
TO ACCESS INDICATOR BASE AND CONFIRM
CABLE PATH.
REMOVAL
WITH ELECTRONIC TRANSMISSION RANGE
INDICATOR
(1) Disconnect and isolate the battery negative
cable.
(2) Remove Over Steering Column Bezel by lifting
it straight up with a firm pull.
(3) Remove the four cluster bezel attaching screws.
(4) Tilt the steering column in the full down posi-
tion.
(5) Pull rearward on the cluster bezel and remove.
(6) Remove the four screws holding instrument
cluster to instrument panel.(7) Rotate top of cluster outward.
(8) Disconnect the cluster harness connector.
(9) Remove instrument cluster from instrument
panel.WITH MECHANICAL TRANSMISSION RANGE
INDICATOR
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the lower steering column cover. Refer
to Body, Instrument Panel, Lower Steering Column
Cover, Removal.
RSINSTRUMENT CLUSTER8J-11
INSTRUMENT CLUSTER (Continued)
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OPERATION - TURN SIGNAL SYSTEM.......21
DIAGNOSIS AND TESTING - MULTI-
FUNCTION SWITCH...................22
REMOVAL.............................22
INSTALLATION.........................22
PARK/TURN SIGNAL LAMP
REMOVAL.............................22
INSTALLATION.........................22
PARK/TURN SIGNAL LAMP - EXPORT
REMOVAL.............................22
INSTALLATION.........................23
REAR FOG LAMP - EXPORT
DESCRIPTION.........................23REPEATER LAMP - EXPORT
REMOVAL.............................23
INSTALLATION.........................23
TAIL LAMP
REMOVAL.............................23
INSTALLATION.........................23
TAIL LAMP - EXPORT
REMOVAL.............................23
INSTALLATION.........................24
TAIL LAMP UNIT
REMOVAL.............................24
INSTALLATION.........................24
LAMPS/LIGHTING - EXTERIOR
DESCRIPTION
LAMP SYSTEMS
Lighting circuits are protected by fuses. Lighting
circuits require an overload protected power source,
on/off device, lamps and body ground to operate prop-
erly. Plastic lamps require a wire in the harness to
supply body ground to the lamp socket. Replace sock-
ets and bulbs that are corroded.
Some of the interior and exterior lighting functions
are governed by the Body Control Module (BCM).
The headlamp, dome, and the door ajar switches pro-
vide signals to the BCM. The BCM in turn sends a
Programmable Communication Interface (PCI) bus
message to the Front Control Module (FCM) to
enable the necessary drivers to set the required illu-
mination configuration.
Wire connectors can make intermittent contact or
become corroded. Before coupling wire connectors,
inspect the terminals inside the connector. Male ter-
minals should not be bent or disengaged from the
insulator. Female terminals should not be sprung
open or disengaged from the insulator. Bent and
sprung terminals can be repaired using needle nose
pliers and pick tool. Corroded terminals appear
chalky or green. Corroded terminals should be
replaced to avoid recurrence of the problem symp-
toms.
Begin electrical system failure diagnosis by testing
related fuses in the fuse block and intelligent power
module. Verify that bulbs are in good condition and
test continuity of the circuit ground. Refer to the
appropriate wiring information.
AUTOMATIC HEADLAMP SYSTEM
The Automatic Headlamp system turns the instru-
mentation and exterior illumination lamps ON when
the ambient light levels are Night and the engine
RPM is 450 or above, and OFF when light levels are
Day.
DAYTIME RUNNING LAMPS
Operating the high-beam headlamps at reduced
power provides daytime running lamps, which are
required on all new Canadian vehicles.
HEADLAMPS ON WITH WINDSHIELD WIPERS
For vehicles equipped with the Automatic Head-
lamp System, the instrumentation and exterior illu-
mination lamps will be turned ON when the
headlamp switch is in the AUTO position, RPM >
450 and the windshield wipers have been in the
intermittent, low or high mode of operation for more
than ten seconds. When the windshield wipers are
turned OFF the Body Control Module will determine
if the instrumentation and exterior illumination
lamps should remain ON base upon the current
ambient light level.
HEADLAMP SYSTEM
The configuration of the headlamp system of head-
lamps, park lamps and fog lamps is determined by
the BCM. The BCM determines the lighting configu-
ration as a result of the inputs from the ignition
switch, headlamp switch and multi-function switch. A
PCI bus is transmitted from the BCM to the FCM to
enable the necessary drivers to set the illumination
configuration. Four wires are connected between the
headlamp switch and the BCM. The first wire con-
tains information regarding the position of the head-
lamp switch (Off, Automatic Headlamps, Automatic
Headlamp switch fog, Park with Fog, Head, or Head
with Fog Lamps). The second wire contains informa-
tion regarding the position of the dimmer switch
(Dome Lamp, Daytime Brightness, Dimming Level or
Off). The third wire is a dedicated signal return
(ground) wire. The fourth wire provides power to the
front fog lamp indicator.
HEADLAMP TIME DELAY SYSTEM
The headlamp time delay system is controlled by
the Body Control Module (BCM) via a PCI bus mes-
8L - 2 LAMPS/LIGHTING - EXTERIORRS
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(3) Install the retaining screws.
(4) Reconnect the battery negative cable.
FOG LAMP
DIAGNOSIS AND TESTING - FOG LAMP
When a vehicle experiences problems with the fog
lamp system, verify the condition of the battery con-
nections, fuses, charging system, fog lamp bulbs, wire
connectors, relay, high beam switch, and headlamp
switch. Refer to the appropriate wiring information.
Each vehicle is equipped with various lamp assem-
blies. A good ground is necessary for proper lighting
operation. Grounding is provided by the lamp socket
when it comes in contact with the metal body, or
through a separate ground wire.
When changing lamp bulbs check the socket for
corrosion. If corrosion is present, clean it with a wire
brush.
When it is necessary to remove components to ser-
vice another, it should not be necessary to apply
excessive force or bend a component to remove it.
Before damaging a trim component, verify hidden
fasteners or captured edges are not holding the com-
ponent in place.
FOG LAMP DIAGNOSIS
CONDITION POSSIBLE CAUSES CORRECTION
FOG LAMPS ARE DIM
WITH ENGINE IDLING
OR IGNITION TURNED
OFF.1. Loose or corroded battery
cables.1. Clean and secure battery cable clamps and
posts.
2. Loose or worn generator drive
belt.2. Adjust or replace generator drive belt.
3. Charging system output too low. 3. Test and repair charging system. Refer to
Electrical, Charging,
4. Battery has insufficient charge. 4. Test battery state-of-charge. Refer to
Electrical, Battery System.
5. Battery is sulfated or shorted. 5. Load test battery. Refer to Electrical, Battery
System.
6. Poor lighting circuit Z349/Z248
ground.6. Test for voltage drop across Z349/248
ground locations. Refer to Electrical, Wiring
Information.
FOG LAMP BULBS
BURN OUT
FREQUENTLY1. Charging system output too
high.1. Test and repair charging system. Refer to
Electrical, Charging.
2. Loose or corroded terminals or
splices in circuit.2. Inspect and repair all connectors and splices.
Refer to Electrical, Wiring Information.
Fig. 6 CHMSL BULB
1 - CHMSL UNIT
2 - CHMSL BULB
RSLAMPS/LIGHTING - EXTERIOR8L-7
CENTER HIGH MOUNTED STOP LAMP UNIT (Continued)
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