ignition DODGE TOWN AND COUNTRY 2001 Repair Manual
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Page 453 of 2321
(2) Disconnect electrical connectors from the cam-
shaft position sensor (Fig. 4).(3) Remove camshaft position sensor mounting
screws. Remove sensor.
(4) Loosen screw attaching target magnet to rear
of camshaft and remove magnet (Fig. 5).
REMOVAL - 3.3/3.8L
(1) Disconnect the negative battery cable.
(2) Remove the air box cover and inlet tube (Fig.
6).
(3) Disconnect camshaft position sensor electrical
connector from the wiring harness connector (Fig. 7).
Fig. 3 Camshaft Sprocket
1 - CAMSHAFT SPROCKET
2 - CYL #6
3 - CYL #5
4 - CYL #4
5 - CYL #3
6 - CYL #2
7 - CYL #1
Fig. 4 EGR/CAM SENSOR 2.4L
Fig. 5 Target Magnet Removal/Installation
1 - TARGET MAGNET
2 - MOUNTING BOLT
3 - REAR OF CYLINDER HEAD
Fig. 6 AIR BOX COVER
8I - 4 IGNITION CONTROLRS
CAMSHAFT POSITION SENSOR (Continued)
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Page 454 of 2321
(4) Remove bolt holding sensor.
(5) Rotate sensor away from block.
(6) Pull sensor up out of the chain case cover.Do
not pull on the sensor lead.There is an O-ring on
the sensor case. The O-ring may make removal diffi-
cult. A light tap to top of sensor prior to removal may
reduce force needed for removal.
INSTALLATION - 2.4L
The target magnet has locating dowels that fit into
machined locating holes in the end of the camshaft
(Fig. 8).(1) Install target magnet in end of camshaft.
Tighten mounting screw to 3 N´m (30 in. lbs.) torque.
Over torqueing could cause cracks in magnet. If mag-
net cracks replace it.
(2) Install camshaft position sensor. Tighten sensor
mounting screws to 12.9 N´m (115 in. lbs.) torque.
(3) Carefully attach electrical connector to cam-
shaft position sensor. Installation at an angle may
damage the sensor pins.
(4) Connect the negative battery cable.
INSTALLATION - 3.3/3.8L
If the removed sensor is reinstalled, clean off
the old spacer on the sensor face. A NEW
SPACER must be attached to the face before
installation.Inspect O-ring for damage, replace if
necessary. If the sensor is being replaced, confirm
that the paper spacer is attached to the face and
O-ring is positioned in groove of the new sensor (Fig.
9).
(1) Apply a couple drops of clean engine oil to the
O-ring prior to installation.
(2) Install sensor in the chain case cover and
rotate into position.
(3) Push sensor down until contact is made with
the camshaft gear. While holding the sensor in this
position, install and tighten the retaining bolt 14
N´m (125 in. lbs.) torque.
(4) Connect camshaft position sensor electrical
connector to harness connector.
(5) Install the air box cover and inlet hose (Fig. 6).
(6) Connect the negative battery cable.
Fig. 7 CAMSHAFT POSITION SENSOR
Fig. 8 Target Magnet Installation
1 - LOCATING DOWELS
2 - LOCATING HOLES (2)
Fig. 9 Camshaft Position Sensor and Spacer
1 - ELECTRICAL CONNECTOR
2 - O-RING
3 - PAPER SPACER
RSIGNITION CONTROL8I-5
CAMSHAFT POSITION SENSOR (Continued)
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Page 455 of 2321
IGNITION COIL
DESCRIPTION
The ignition coil assembly consists of 2 or 3 inde-
pendent coils molded together (Fig. 10) or (Fig. 11).
The coil assembly for the 3.3/3.8L is mounted on the
intake manifold. The coil assembly for the 2.4L is
mounted on the cylinder head cover. Spark plug
cables route to each cylinder from the coil.
OPERATION
The coil fires two spark plugs every power stroke.
One plug is the cylinder under compression, the
other cylinder fires on the exhaust stroke. The Pow-
ertrain Control Module (PCM) determines which of
the coils to charge and fire at the correct time.
The Auto Shutdown (ASD) relay provides battery
voltage to the ignition coil. The PCM provides a
ground contact (circuit) for energizing the coil. When
the PCM breaks the contact, the magnetic energy in
the coil transfers to the secondary causing the spark.
The PCM will de-energize the ASD relay if it does
not receive the crankshaft position sensor and cam-
shaft position sensor inputs. Refer to Auto Shutdown
(ASD) RelayÐPCM Output, in this section for relay
operation.
REMOVAL - 2.4L
The electronic ignition coil pack attaches directly
to the valve cover.
(1) Diconnect the negative battery cable.
(2) Disconnect electrical connector from coil pack
(3) Remove coil pack mounting bolts.(4) Remove coil pack and heat shield (Fig. 10).
REMOVAL - 3.3/3.8L
(1) Disconnect the negative battery cable.
(2) Remove the throttle and speed control cables
from clip.
(3) Remove 2 bolts from the Power steering reser-
voir to intake manifold.
(4) Loosen the lower nut for the power steering
reservoir from stud on ignition coil bracket.
(5) Reposition the Power steering reservoir (Fig.
12).
(6) Remove the ignition cables from the ignition
coil.
(7) Disconnect the electrical connector from the
ignition coil.
(8) Remove 2 nuts from the ignition coil studs.
(9) Remove 2 bolts from ignition coil, remove coil.
INSTALLATION - 2.4L
(1) Install ignition coil and heat shield to valve
cover and tighten bolts.
(2) Connect the electrical connector to the ignition
coil.
(3) Transfer spark plug cables to new coil pack.
The coil pack towers are numbered with the cylinder
identification. Be sure the ignition cables are fully
seated onto the towers.
(4) Connect the negative battery cable.
Fig. 10 IGNITION COIL - 2.4L
Fig. 11 IGNITION COIL - 3.3/3.8L
1 - IGNITION COIL
8I - 6 IGNITION CONTROLRS
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INSTALLATION - 3.3/3.8L
(1) Install coil over studs on bracket.
(2) Install 2 bolts to ignition coil.
(3) Install 2 nuts to the ignition coil studs. Tighten
nuts and bolts.
(4) Connect the electrical connector to the ignition
coil.
(5) Install the ignition cables to the ignition coil.
(6) Reposition the Power steering reservoir. Slide
bracket over the mounting stud (Fig. 12).
(7) Install 2 bolts the Power steering reservoir to
intake manifold.
(8) Tighten the lower nut to stud on ignition coil
bracket.
(9) Install the throttle and speed control cables to
clip.
(10) Connect the negative battery cable.
KNOCK SENSOR
DESCRIPTION
The knock sensor threads into the cylinder block.
The knock sensor is designed to detect engine vibra-
tion that is caused by detonation.
OPERATION
When the knock sensor detects a knock in one of
the cylinders, it sends an input signal to the PCM. In
response, the PCM retards ignition timing for all cyl-
inders by a scheduled amount.Knock sensors contain a piezoelectric material
which constantly vibrates and sends an input voltage
(signal) to the PCM while the engine operates. As the
intensity of the crystal's vibration increases, the
knock sensor output voltage also increases.
The voltage signal produced by the knock sensor
increases with the amplitude of vibration. The PCM
receives as an input the knock sensor voltage signal.
If the signal rises above a predetermined level, the
PCM will store that value in memory and retard
ignition timing to reduce engine knock. If the knock
sensor voltage exceeds a preset value, the PCM
retards ignition timing for all cylinders. It is not a
selective cylinder retard.
The PCM ignores knock sensor input during engine
idle conditions. Once the engine speed exceeds a
specified value, knock retard is allowed.
Knock retard uses its own short term and long
term memory program.
Long term memory stores previous detonation
information in its battery-backed RAM. The maxi-
mum authority that long term memory has over tim-
ing retard can be calibrated.
Short term memory is allowed to retard timing up
to a preset amount under all operating conditions (as
long as rpm is above the minimum rpm) except WOT.
The PCM, using short term memory, can respond
quickly to retard timing when engine knock is
detected. Short term memory is lost any time the
ignition key is turned off.
NOTE: Over or under tightening affects knock sen-
sor performance, possibly causing improper spark
control.
REMOVAL - 2.4L
The knock sensor threads into the side of the cyl-
inder block in front of the starter (Fig. 13).
(1) Disconnect electrical connector from knock sen-
sor.
(2) Use a crow foot socket to remove the knock
sensors.
REMOVAL - 3.8L
The knock sensor threads into the side of the cyl-
inder block in the rear.
(1) Disconnect the negative battery cable.
(2) Raise vehicle and support.
(3) On All Wheel Drive vehicles remove the PTU
(Power Transfer Unit), refer to the Transmission sec-
tion for more information.
(4) Disconnect electrical connector from knock sen-
sor.
(5) Use a crow foot socket to remove the knock
sensor.
Fig. 12 IGNITION COIL BRACKET 3.3/3.8L
RSIGNITION CONTROL8I-7
IGNITION COIL (Continued)
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Page 457 of 2321
INSTALLATION - 2.4L
The knock sensor threads into the side of the cyl-
inder block in front of the starter (Fig. 13).
(1) Install knock sensor. Tighten knock sensor to
10 N´m (7 ft. lbs.) torque.Over or under tighten-
ing effects knock sensor performance, possibly
causing improper spark control.
(2) Attach electrical connector to knock sensor.
INSTALLATION - 3.8L
The knock sensor threads into the side of the cyl-
inder block in the rear.
(1) Install knock sensor. Tighten knock sensor to
10 N´m (7 ft. lbs.) torque.Over or under tighten-
ing effects knock sensor performance, possibly
causing improper spark control.
(2) Attach electrical connector to knock sensor.
(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 - STANDARD 2.4L
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 3.3/3.8L
These engines utilize platinum spark plugs. Refer
to the maintenance schedule.
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.
The spark plugs are double platinum and 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 sched-
ule B in this manual. A thin platinum pad is welded
to both electrode ends as show in (Fig. 14). Extreme
care must be used to prevent spark plug cross
threading, mis-gaping and ceramic insulator damage
during plug removal and installation.
Fig. 13 Knock Sensor
1 - GENERATOR
2 - INTAKE MANIFOLD
3 - KNOCK SENSOR
4-STARTER
Fig. 14 Platinum Pads
1 - APPLY ANTI-SEIZE COMPOUND HERE ONLY
2 - PLATINUM SPARK SURFACE
8I - 8 IGNITION CONTROLRS
KNOCK SENSOR (Continued)
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Page 458 of 2321
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.
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. 15 Setting Spark Plug Electrode Gap
1 - TAPER GAUGE
RSIGNITION CONTROL8I-9
SPARK PLUG (Continued)
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INSTRUMENT CLUSTER
TABLE OF CONTENTS
page page
INSTRUMENT CLUSTER
DESCRIPTION............................1
OPERATION.............................1
DIAGNOSIS AND TESTING..................1
INSTRUMENT CLUSTER..................1
REMOVAL..............................11
INSTALLATION...........................11
CLUSTER LENS
REMOVAL..............................12INSTALLATION...........................12
MECHANICAL TRANSMISSION RANGE
INDICATOR
REMOVAL..............................12
INSTALLATION...........................12
RED BRAKE WARNING INDICATOR
DESCRIPTION...........................12
OPERATION.............................12
INSTRUMENT CLUSTER
DESCRIPTION
The instrumentation gauges are contained in a
subdial assembly within the instrument cluster. The
individual gauges are not serviceable. If one of the
cluster gauges becomes faulty, the entire cluster
would require replacement.
The mechanical instrument cluster with a tachom-
eter is equipped with a electronic vacuum fluorescent
transmission range indicator (PRND3L), odometer,
and trip odometer display.
The mechanical instrument cluster without a
tachometer is equipped with a cable operated trans-
mission range indicator (PRND21) and a vacuum
flourescent odometer display.
The instrument cluster is equipped with the follow-
ing warning lamps.
²Lift Gate Ajar
²Low Fuel Level
²Low Windshield Washer Fluid Level
²Cruise
²Battery Voltage
²Fasten Seat Belt
²Door Ajar
²Headlamp Out
²Coolant Temperature
²Anti-Lock Brake
²Brake
²Airbag
²Traction Control
²Autostick
OPERATION
Refer to the vehicle Owner's Manual for operation
instructions and conditions for the Instrument Clus-
ter Gauges.
DIAGNOSIS AND TESTING - SELF-
DIAGNOSTICS
The instrument clusters are equipped with a self
diagnostic test feature to help identify electronic
problems. Prior to any test, perform the Self-Diag-
nostic Test. The self diagnostic system displays
instrument cluster stored fault codes in the odometer
display, sweeps the gauges to the calibration points,
and bulb checks the warning indicators. When the
key is in the ON position with the engine not run-
ning, the MIL will remain illuminated for regulatory
purposes.
To activate the Self-Diagnostic program:
(1) With the ignition switch in the OFF position,
depress the TRIP ODOMETER RESET button.
(2) Continue to hold the TRIP ODOMETER
RESET button untilSofand a number (software ver-
sion number (i.e.Sof 3.2) appears in the odometer
window (about five seconds) then release the button.
If a fault code is present, the cluster will display it in
the odometer display. When all fault codes have been
displayed, the cluster will displayªendºin the odom-
eter display. Refer to the table to determine what
each trouble code means.
RSINSTRUMENT CLUSTER8J-1
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CONDITIONS
Refer to the following tables for possible problems,
causes, and corrections.
²INSTRUMENT CLUSTER
²SPEEDOMETER DIAGNOSIS
²TACHOMETER DIAGNOSIS
²FUEL GAUGE DIAGNOSIS
²TEMPERATURE GAUGE DIAGNOSIS²ODOMETER DIAGNOSIS
²ELECTRONIC GEAR INDICATOR DISPLAY
DIAGNOSIS
²MECHANICAL TRANSMISSION RANGE INDI-
CATOR (PRND21) DIAGNOSIS
NOTE: Always check the functionality of the cluster
by running the self test prior to troubleshooting.
INSTRUMENT CLUSTER
CONDITION POSSIBLE CAUSES CORRECTION
INSTRUMENT CLUSTER
INOPERATIVE.
NO RESPONSE FROM
INSTRUMENT CLUSTER.NO PCI BUS MESSAGES
FROM THE BCM.1. USE A DRB IIITSCAN TOOL TO CHECK THE
BCM. IF OK, LOOK FOR ANOTHER POSSIBLE
CAUSE FOR CLUSTER FAILURE. IF NOT OK,
REFER TO THE PROPER BODY DIAGNOSTIC
PROCEDURES MANUAL.
SPREAD TERMINAL(S)
ON WIRING HARNESS
CLUSTER CONNECTOR.1. REMOVE CLUSTER FROM INSTRUMENT PANEL
AND CHECK WIRING HARNESS CONNECTOR FOR
SPREAD TERMINAL. IF OK, LOOK FOR ANOTHER
POSSIBLE CAUSE FOR THE CLUSTER FAILURE. IF
NOT OK, REPAIR CONNECTOR.
BCM IS NOT RECEIVING
PROPER INPUT FROM
THE IGNITION SWITCH.1. USE A DRB IIITSCAN TOOL TO VERIFY IGNITION
SWITCH STATUS INTO THE BCM. IF NOT OK, GO
TO STEP (2). IF OK, LOOK AT ANOTHER POSSIBLE
CAUSE OF FAILURE.
2. CHECK IGNITION SWITCH FUNCTION AND
WIRING.
INTERNAL CLUSTER
FAILURE.1. REPLACE CLUSTER.
WAKE UP CIRCUIT
FAULTY.VERIFY CONTINUITY OF WAKE UP CIRCUIT FROM
BCM TO MIC. CIRCUIT SHALL BE LOW WHENEVER
BCM IS AWAKE.
POWER OR GROUND
MISSING.IF NO RESPONSE FROM THE MIC, CHECK FOR
POWER AND GROUND AT THE MIC CONNECTOR.
REFER TO WIRING DIAGRAMS FOR CONNECTOR
CALL OUTS.
RSINSTRUMENT CLUSTER8J-3
INSTRUMENT CLUSTER (Continued)
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Page 471 of 2321
(11) Install the lower steering column cover. Refer
to Body, Instrument Panel, Lower Steering Column
Cover, Installation.
(12) Connect the battery negative cable.
CLUSTER LENS
REMOVAL
(1) Remove the instrument cluster. Refer to Elec-
trical, Instrument Cluster, Removal.
(2) Remove the screws holding the lens to the
instrument cluster.
(3) Press down on the snap features of the lens
and remove the lens from the cluster.
INSTALLATION
(1) Insert the lens snap features into the cluster.
(2) Install the screws holding the lens to the
instrument cluster.
(3) Install the instrument cluster. Refer to Electri-
cal, Instrument Cluster, Installation.
MECHANICAL TRANSMISSION
RANGE INDICATOR
REMOVAL
(1) Remove the instrument cluster and disconnect
the range indicator cable at both attaching points.
Refer to Electrical, Instrument Cluster, Removal.
(2) From the backside of the cluster, remove two
screws holding the mechanical transmission rangeindicator and then remove it fromt instrument clus-
ter.
INSTALLATION
(1) Insert the mechanical transmission range indi-
cator into the backside of the instrument cluster and
install the two screws.
(2) Install the instrument cluster. Refer to Electri-
cal, Instrument Cluster, Installation.
RED BRAKE WARNING
INDICATOR
DESCRIPTION
The red BRAKE warning indicator (lamp) is
located in the instrument panel cluster and is used to
indicate a low brake fluid condition or that the park-
ing brake is applied. In addition, the brake warning
indicator is turned on as a bulb check by the ignition
switch every time the ignition switch is placed in the
crank position.
OPERATION
The red BRAKE warning indicator (lamp) is sup-
plied a 12-volt ignition feed anytime the ignition
switch is on. The bulb is then illuminated by com-
pleting the ground circuit either through the switch
on the parking brake lever, the brake fluid level
switch in the master cylinder reservoir, or the igni-
tion switch when it is placed in the crank position.
8J - 12 INSTRUMENT CLUSTERRS
INSTRUMENT CLUSTER (Continued)
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LAMPS/LIGHTING - EXTERIOR
DESCRIPTION
LAMP SYSTEMS
RS vehicles use lighting on the interior and exte-
rior of the vehicle for illuminating and indicating
purposes. Lighting circuits are protected by fuses.
Lighting circuits require an overload protected power
source, on/off device, lamps and body ground to oper-
ate properly. Plastic lamps require a wire in the har-
ness to supply body ground to the lamp socket.
Replace sockets and bulbs that are corroded.
Some of the interior and exterior lighting functions
are governed by the Body Control Module. The head-
lamp, dome, and the door ajar switches provide sig-
nals to the Body Control Module. The Body Control
Module in turn sends a J1850 message to the Front
Control Module (FCM) to enable the necessary driv-
ers to set the required illumination configuration.
Wire connectors can make intermittent contact or
become corroded. Before coupling wire connectors,
inspect the terminals inside the connector. Male termi-
nals should not be bent or disengaged from the insu-
lator. Female terminals should not be sprung open or
disengaged from the insulator. Bent and sprung termi-
nals can be repaired using needle nose pliers and pick
tool. Corroded terminals appear chalky or green. Cor-
roded terminals should be replaced to avoid recur-
rence of the problem symptoms.
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. The wiring informa-
tion includes wiring diagrams, proper wire and con-
nector repair procedures, details of wire harness
routing and retention, connector pin-out information
and location views for the various wire harness con-
nectors, splices and grounds.
AUTOMATIC HEADLAMP SYSTEM
The Automatic Headlamp system turns the instru-
mentation and exterior illumination lamps ON when
the ambient light levels are Night 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 theheadlamp 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 multifunction switch. A
J1850 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 J1850 message
transmitted by the BCM to the FCM to turn off the
headlamps.
OPERATION
AUTOMATIC HEADLAMP SYSTEM
Automatic headlamps are controlled by the Body
Control Module (BCM). With the headlamp switch in
the AUTO position, the BCM will control the head-
lamp, parking, side marker, tail and instrumentation
lamps based on ambient light levels. Ambient light
levels are monitored by the BCM using the Day/
Night signal and Electrochromatic Mirror (ECM)
present from the Compass Mini Trip (CMTC) located
on the front windshield in front of the rear view mir-
ror (ECM). Ambient light readings are averaged to
limit cycling the lamps ON and OFF when passing
through areas with varying light levels. The auto-
matic headlamps will only function when the engine
is running with RPM > 450. When the headlamp
switch is in the AUTO position (Automatic mode), the
Headlamp Time Delay system will function when the
ignition switch is placed in any position other than
run/start.
8L - 2 LAMPS/LIGHTING - EXTERIORRS
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