1998 DODGE RAM 1500 low beam

INDICATORS
Indicators are located in various positions within
the EMIC and are all connected to the EMIC elec-
tronic circuit board. The cargo lamp indicator, door
ajar indicator, high beam indicator, and turn signal
indicators operate based upon hard wired inputs to
the EMIC. The brake indicator is controlled by PCI
data bus messages from the Controller Antilock
Brake (CAB) as well as by hard wired park brake
switch inputs to the EMIC. The seatbelt indicator is
controlled by the EMIC programming, PCI data bus
messages from the Airbag Control Module (ACM),
and a hard wired seat belt switch input to the EMIC.
The Malfunction Indicator Lamp (MIL) is normally
controlled by PCI data bus messages from the Pow-
ertrain Control Module (PCM); however, if the EMIC
loses PCI data bus communication, the EMIC cir-
cuitry will automatically turn the MIL on until PCI
data bus communication is restored. The EMIC uses
PCI data bus messages from the Front Control Mod-
ule (FCM), the PCM, the diesel engine only Engine
Control Module (ECM), the ACM, the CAB, and the
Sentry Key Immobilizer Module (SKIM) to control all
of the remaining indicators.
The various EMIC indicators are controlled by dif-
ferent strategies; some receive fused ignition switch
output from the EMIC circuitry and have a switched
ground, while others are grounded through the EMIC
circuitry and have a switched battery feed. However,
all indicators are completely controlled by the EMIC
microprocessor based upon various hard wired and
electronic message inputs. All indicators are illumi-
nated at a fixed intensity, which is not affected by
the selected illumination intensity of the EMIC gen-
eral illumination lamps.
In addition, certain indicators in this instrument
cluster are automatically configured or self-config-
ured. This feature allows the configurable indicators
to be enabled by the EMIC circuitry for compatibility
with certain optional equipment. The EMIC defaults
for the ABS indicator and airbag indicator are
enabled, and these configuration settings must be
programmatically disabled in the EMIC using a
DRBIIItscan tool for vehicles that do not have this
equipment. The automatically configured or self-con-
figured indicators remain latent in each EMIC at all
times and will be active only when the EMIC
receives the appropriate PCI message inputs for that
optional system or equipment.
The hard wired indicator inputs may be diagnosed
using conventional diagnostic methods. However, the
EMIC circuitry and PCI bus message controlled indi-
cators are diagnosed using the EMIC self-diagnosticactuator test. (Refer to 8 - ELECTRICAL/INSTRU-
MENT CLUSTER - DIAGNOSIS AND TESTING).
Proper testing of the PCI data bus and the electronic
message inputs to the EMIC that control an indicator
requires the use of a DRBIIItscan tool. Refer to the
appropriate diagnostic information. Specific details of
the operation for each indicator may be found else-
where in this service information.
CLUSTER ILLUMINATION
The EMIC has several illumination lamps that are
illuminated when the exterior lighting is turned on
with the headlamp switch. The illumination intensity
of these lamps is adjusted when the interior lighting
thumbwheel on the headlamp switch is rotated (down
to dim, up to brighten) to one of six available minor
detent positions. The EMIC monitors a resistor mul-
tiplexed input from the headlamp switch on a dim-
mer input circuit. In response to that input, the
EMIC electronic circuitry converts a 12-volt input it
receives from a fuse in the Integrated Power Module
(IPM) on a hard wired panel lamps dimmer switch
signal circuit into a 12-volt Pulse Width Modulated
(PWM) output. The EMIC uses this PWM output to
power the cluster illumination lamps and the VFD
units on the EMIC circuit board, then provides a syn-
chronized PWM output on the various hard wired
fused panel lamps dimmer switch signal circuits to
control and synchronize the illumination intensity of
other incandescent illumination lamps in the vehicle.
The cluster illumination lamps are grounded at all
times.
The EMIC also sends electronic dimming level
messages over the PCI data bus to other electronic
modules in the vehicle to control and synchronize the
illumination intensity of their VFD units to that of
the EMIC VFD units. In addition, the thumbwheel
on the headlamp switch has a Parade Mode position
to provide a parade mode. The EMIC monitors the
request for this mode from the headlamp switch,
then sends an electronic dimming level message over
the PCI data bus to illuminate all VFD units in the
vehicle at full (daytime) intensity for easier visibility
when driving in daylight with the exterior lighting
turned on.
The hard wired headlamp switch and EMIC panel
lamps dimmer inputs and outputs may be diagnosed
using conventional diagnostic methods. However,
proper testing of the PWM output of the EMIC and
the electronic dimming level messages sent by the
EMIC over the PCI data bus requires the use of a
DRBIIItscan tool. Refer to the appropriate diagnos-
tic information.
DRINSTRUMENT CLUSTER 8J - 9
INSTRUMENT CLUSTER (Continued)

INPUT AND OUTPUT CIRCUITS
HARD WIRED INPUTS
The hard wired inputs to the EMIC include the fol-
lowing:
²Brake Lamp Switch Output
²Driver Cylinder Lock Switch Sense
²Driver Door Ajar Switch Sense
²Driver Door Lock Switch MUX - with
Power Locks
²Fused B(+) - Ignition-Off Draw
²Fused B(+) - Power Lock Feed - with Power
Locks
²Fused Ignition Switch Output (Accessory-
Run)
²Fused Ignition Switch Output (Off-Run-
Start)
²Fused Ignition Switch Output (Run-Start)
²Headlamp Dimmer Switch MUX
²Headlamp Switch MUX
²Horn Relay Control
²Key-In Ignition Switch Sense
²Left Rear Door Ajar Switch Sense
²Panel Lamps Dimmer Switch Signal
²Park Brake Switch Sense
²Passenger Door Ajar Switch Sense
²Passenger Door Lock Switch MUX - with
Power Locks
²Radio Control MUX
²Right Rear Door Ajar Switch Sense
²RKE Supply - with RKE
²Seat Belt Switch Sense
²Transmission Range Sensor MUX - with
Auto Trans
²Turn/Hazard Switch MUX
²Washer/Beam Select Switch MUX
²Wiper Switch MUX
Refer to the appropriate wiring information for
additional details.
HARD WIRED OUTPUTS
The hard wired outputs of the EMIC include the
following:
²Accessory Switch Bank Illumination Driver
²BTSI Driver - with Auto Trans
²Cargo Lamp Driver
²Dome/Overhead Lamp Driver
²Driver Door Unlock Driver - with Power
Locks
²Headlamp Switch Illumination Driver
²Heated Seat Switch Indicator Driver - with
Heated Seats
²Heater-A/C Control Illumination Driver
²Left Door Lock Driver - with Power Locks
²Left Rear Door Unlock Driver - with Power
Locks²Map/Glove Box Lamp Driver
²Radio Illumination Driver
²Right Door Lock Driver - with Power Locks
²Right Door Unlock Driver - with Power
Locks
²Transfer Case Switch Illumination Driver -
with Four-Wheel Drive
Refer to the appropriate wiring information for
additional details.
GROUNDS
The EMIC receives and supplies a ground path to
several switches and sensors through the following
hard wired circuits:
²Ground - Illumination (2 Circuits)
²Ground - Power Lock - with Power Locks
²Ground - Signal
²Headlamp Switch Return
²Multi-Function Switch Return
²Transmission Range Sensor Return - with
Auto Trans
Refer to the appropriate wiring information for
additional details.
COMMUNICATION
The EMIC has provisions for the following commu-
nication circuits:
²PCI Data Bus
²RKE Program Serial Data - with RKE
²RKE Transmit Serial Data - with RKE
Refer to the appropriate wiring information for
additional details.
DIAGNOSIS AND TESTING - INSTRUMENT
CLUSTER
If all of the instrument cluster gauges and/or indi-
cators are inoperative, refer to PRELIMINARY
DIAGNOSIS. If an individual gauge or Programma-
ble Communications Interface (PCI) data bus mes-
sage-controlled indicator is inoperative, refer to
ACTUATOR TEST. If an individual hard wired indi-
cator is inoperative, refer to the diagnosis and testing
information for that specific indicator.
Refer to the appropriate wiring information. The
wiring information includes wiring diagrams, proper
wire and connector repair procedures, details of wire
harness routing and retention, connector pin-out
information and location views for the various wire
harness connectors, splices and grounds.
8J - 10 INSTRUMENT CLUSTERDR
INSTRUMENT CLUSTER (Continued)

upon electronic messages received from the electronic
Transmission Control Module (TCM) over the Pro-
grammable Communications Interface (PCI) data
bus. If the transmission range sensor mux circuit is
open and no electronic messages are received from
the TCM within two seconds, the instrument cluster
circuitry will not display any gear selector position
until the condition is resolved or until the ignition
switch is turned to the Off position, whichever occurs
first.
²Resolved Circuit- If the transmission range
sensor mux circuit is resolved, the cluster circuitry
controls the gear selector indicator display based
upon the resistance value of the hard wired input
from the transmission range sensor. If the cluster is
configured for an automatic transmission with a
transmission range sensor input and detects a short
to ground or an open in the transmission range sen-
sor mux input, the instrument cluster circuitry will
not display any gear selector position in the VFD.
The VFD display for the short-to-ground and open
circuit conditions will continue until the condition is
resolved or until the ignition switch is turned to the
Off position, whichever occurs first.
²Actuator Test- Each time the cluster is put
through the actuator test, the gear selector indicator
VFD will display all of its characters at once during
the VFD portion of the test to confirm the function-
ality of the VFD and the cluster control circuitry.
On models with a TCM, the TCM continually mon-
itors the transmission range sensor, then sends the
proper gear selector indicator position messages to
the instrument cluster. On models without a TCM,
the instrument cluster continually monitors the hard
wired transmission range sensor multiplexed input.
For further diagnosis of the gear selector indicator or
the instrument cluster circuitry that controls this
function, (Refer to 8 - ELECTRICAL/INSTRUMENT
CLUSTER - DIAGNOSIS AND TESTING). For fur-
ther diagnosis of the transmission range sensor on
models without a TCM, (Refer to 21 - TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 42RE/TRANS-
MISSION RANGE SENSOR - DIAGNOSIS AND
TESTING) or (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 46RE/TRANSMISSION
RANGE SENSOR - DIAGNOSIS AND TESTING).
On models with a TCM, for proper diagnosis of the
transmission range sensor, the TCM, the PCI data
bus, or the electronic message inputs to the instru-
ment cluster that control the gear selector indicator,
a DRBIIItscan tool is required. Refer to the appro-
priate diagnostic information.HIGH BEAM INDICATOR
DESCRIPTION
A high beam indicator is standard equipment on
all instrument clusters (Fig. 19). The high beam indi-
cator is located near the upper edge of the instru-
ment cluster, between the tachometer and the
speedometer. The high beam indicator consists of a
stencil-like cutout of the International Control and
Display Symbol icon for ªHigh Beamº in the opaque
layer of the instrument cluster overlay. The dark
outer layer of the overlay prevents the indicator from
being clearly visible when the it is not illuminated. A
blue Light Emitting Diode (LED) behind the cutout
in the opaque layer of the overlay causes the icon to
appear in blue through the translucent outer layer of
the overlay when the indicator is illuminated from
behind by the LED, which is soldered onto the
instrument cluster electronic circuit board. The high
beam indicator is serviced as a unit with the instru-
ment cluster.
OPERATION
The high beam indicator gives an indication to the
vehicle operator whenever the headlamp high beams
are illuminated. This indicator is controlled by a
transistor on the instrument cluster circuit board
based upon cluster programming and a hard wired
multiplex input received by the cluster from the
headlamp beam select switch circuitry of the multi-
function switch on the washer/beam select switch
mux circuit. The high beam indicator Light Emitting
Diode (LED) is completely controlled by the instru-
ment cluster logic circuit, and that logic will allow
this indicator to operate whenever the instrument
cluster receives a battery current input on the fused
B(+) circuit. Therefore, the LED can be illuminated
regardless of the ignition switch position. The LED
only illuminates when it is provided a path to ground
by the instrument cluster transistor. The instrument
cluster will turn on the high beam indicator for the
following reasons:
²High Beam Headlamps-On Input- Each time
the cluster detects a high beam headlamps-on input
from the headlamp beam select switch circuitry of
the multi-function switch on the washer/beam select
switch mux circuit, the headlamp high beams and
the high beam indicator will be illuminated. The
headlamp high beams and the high beam indicator
remain illuminated until the cluster receives a high
beam headlamps-off input from the multi-function
switch, or until the exterior lamp load shedding (bat-
Fig. 19 High Beam Indicator
8J - 28 INSTRUMENT CLUSTERDR
GEAR SELECTOR INDICATOR (Continued)

tery saver) timed interval expires, whichever occurs
first.
²Actuator Test- Each time the cluster is put
through the actuator test, the high beam indicator
will be turned on, then off again during the bulb
check portion of the test to confirm the functionality
of the LED and the cluster control circuitry.
The instrument cluster continually monitors the
headlamp switch and the multi-function switch to
determine the proper headlamp low beam and high
beam control. The instrument cluster then sends the
proper low beam and high beam lamp-on and lamp-
off messages to the Front Control Module (FCM) over
the Programmable Communications Interface (PCI)
data bus and turns the high beam indicator on or off
accordingly. For further diagnosis of the high beam
indicator or the instrument cluster circuitry that con-
trols the indicator, (Refer to 8 - ELECTRICAL/IN-
STRUMENT CLUSTER - DIAGNOSIS AND
TESTING). For proper diagnosis of the headlamps, or
the headlamp switch and multi-function switch
inputs to the instrument cluster that control the high
beam indicator, a DRBIIItscan tool is required.
Refer to the appropriate diagnostic information.
LAMP OUT INDICATOR
DESCRIPTION
A lamp out indicator is standard equipment on all
instrument clusters (Fig. 20). The lamp out indicator
consists of the words ªLAMP OUTº, which appear in
the lower portion of the odometer/trip odometer Vac-
uum-Fluorescent Display (VFD) unit. The VFD is sol-
dered onto the cluster electronic circuit board and is
visible through a window with a smoked clear lens
located on the lower edge of the tachometer gauge
dial face of the cluster overlay. The dark lens over
the VFD prevents the indicator from being clearly
visible when it is not illuminated. The words ªLAMP
OUTº appear in an amber color and at the same
lighting level as the odometer/trip odometer informa-
tion when they are illuminated by the instrument
cluster electronic circuit board. The lamp out indica-
tor is serviced as a unit with the VFD in the instru-
ment cluster.
OPERATION
The lamp out indicator gives an indication to the
vehicle operator when an exterior lamp has failed.
This indicator is controlled by the instrument clustercircuit board based upon cluster programming and
electronic messages received by the cluster from the
Front Control Module (FCM) over the Programmable
Communications Interface (PCI) data bus. The lamp
out indicator is completely controlled by the instru-
ment cluster logic circuit, and that logic will only
allow this indicator to operate when the instrument
cluster receives a battery current input on the fused
ignition switch output (run-start) circuit. Therefore,
the indicator will always be off when the ignition
switch is in any position except On or Start. The
indicator only illuminates when it is switched to
ground by the instrument cluster circuitry. The
instrument cluster will turn on the lamp out indica-
tor for the following reasons:
²Lamp Out Indicator Lamp-On Message-
Each time the cluster receives a lamp out indicator
lamp-on message from the FCM indicating that an
inoperative headlamp (low or high beam), turn signal
lamp, or brake lamp (excluding Center High
Mounted Stop Lamp [CHMSL]) circuit has been
detected, the lamp out indicator is illuminated. The
indicator remains illuminated until the cluster
receives a lamp out indicator lamp-off message from
the FCM or until the ignition switch is turned to the
Off position, whichever occurs first.
²Actuator Test- Each time the cluster is put
through the actuator test, the lamp out indicator will
be turned on, then off again during the VFD portion
of the test to confirm the functionality of the VFD
and the cluster control circuitry.
The FCM monitors each of the headlamp, turn sig-
nal lamp, and brake lamp (except CHMSL) circuits to
determine the condition of these exterior lamps. The
FCM then sends the proper lamp out indicator
lamp-on and lamp-off messages to the instrument
cluster. For further diagnosis of the lamp out indica-
tor or the instrument cluster circuitry that controls
the indicator, (Refer to 8 - ELECTRICAL/INSTRU-
MENT CLUSTER - DIAGNOSIS AND TESTING).
For proper diagnosis of the exterior lighting system
circuits, the FCM, the PCI data bus, or the electronic
message inputs to the instrument cluster that control
the lamp out indicator, a DRBIIItscan tool is
required. Refer to the appropriate diagnostic infor-
mation.
Fig. 20 Lamp Out Indicator
DRINSTRUMENT CLUSTER 8J - 29
HIGH BEAM INDICATOR (Continued)

MARKER LAMP UNIT
REMOVAL
REMOVAL - FENDER MARKER LAMP......17
REMOVAL - TAILGATE MARKER LAMP.....18
INSTALLATION
INSTALLATION - FENDER MARKER LAMP . . 18
INSTALLATION - TAILGATE MARKER LAMP . 18
MULTI-FUNCTION SWITCH
DESCRIPTION - TURN SIGNAL SYSTEM.....18
OPERATION - TURN SIGNAL SYSTEM.......18
DIAGNOSIS AND TESTING - MULTI-
FUNCTION SWITCH...................18
REMOVAL.............................19
INSTALLATION.........................19
PARK LAMP RELAY
DESCRIPTION.........................20
OPERATION...........................20
DIAGNOSIS AND TESTING - PARK LAMP
RELAY..............................20
REMOVAL.............................21
INSTALLATION.........................21
PARK/TURN SIGNAL LAMP
REMOVAL.............................21
INSTALLATION.........................21
TAIL LAMP
REMOVAL
REMOVAL - WITH CARGO BOX..........22REMOVAL - WITHOUT CARGO BOX.......22
INSTALLATION
INSTALLATION - WITH CARGO BOX.......22
INSTALLATION - WITHOUT CARGO BOX . . . 22
TAIL LAMP UNIT
REMOVAL
REMOVAL - WITH CARGO BOX..........22
REMOVAL - WITHOUT CARGO BOX.......23
INSTALLATION
INSTALLATION - WITH CARGO BOX.......23
INSTALLATION - WITHOUT CARGO BOX . . . 23
TRAILER TOW WIRING
DESCRIPTION.........................24
TURN LAMP
REMOVAL
REMOVAL - WITH CARGO BOX..........24
REMOVAL - WITHOUT CARGO BOX.......24
INSTALLATION
INSTALLATION - WITH CARGO BOX.......24
INSTALLATION - WITHOUT CARGO BOX . . . 24
UNDERHOOD LAMP
REMOVAL.............................25
INSTALLATION.........................25
UNDERHOOD LAMP UNIT
REMOVAL.............................25
INSTALLATION.........................25
LAMPS/LIGHTING - EXTERIOR
DESCRIPTION
The exterior lighting system for this model include
the following components:
²Backup Lamps
²Brake Lamps
²Daytime Running Lamps
²Front Fog Lamps
²Hazard Warning Lamps
²Headlamps
²Park Lamps
²Turn Signal Lamps
Other components of the exterior lighting system
for this model include:
²Backup Lamp Switch
²Brake Lamp Switch
²Front Control Module
²Front Fog Lamp Relay
²Hazard Switch
²Multi-Function Switch
²Park Lamp Relay
²Trailer Tow Connectors
Some of the interior and exterior lighting functions
are governed by the front control module. The head-
lamp, dome, and door ajar switchs provide signals to
the instrument cluster. The instrument cluster sends
a J1850 message to the front control module to
enable the necessary components for illumination.Hard wired circuitry connects the exterior lighting
system components to the electrical system of the
vehicle. Refer to the appropriate wiring information.OPERATION
DAYTIME RUNNING LAMPS
Power is reduced using pulse-width modulation to
the high beams, where by the power is switched on
and off rapidly instead of remaining on continuously.
The duration and interval of the power pulses is pro-
grammed into the Front Control Module (FCM).
HEADLAMP SYSTEM
The instrument cluster monitors both the multi-
plexed headlamp and multifunction switches. The
instrument cluster transmits a J1850 bus message to
the front control module (FCM) to activate the head-
lamps. The headlamp system will default to head-
lamps ON position when ignition switch is ON and
when an open or short circuit failure occurs on the
headlamp switch input to the instrument cluster. The
system will return to normal operation when the
open or short is repaired. A fault will be reported by
the Instrument Cluster when a failure occurs on the
dimmer or headlamp switch input.
If the exterior lamps are ON, and the headlamp
switch is in any position other than OFF, with the
ignition switch OFF (LOCK) after 5 minutes, the
8L - 2 LAMPS/LIGHTING - EXTERIORDR

Instrument Cluster transmits a message via J1850
informing the the FCM. The FCM will then turn off
the headlamps, park lamps and fog lamps. This fea-
ture (load shed) prevents the vehicle battery from
being discharged when the vehicle lights have been
left ON.
HEADLAMP TIME DELAY SYSTEM
The headlamp time delay system is activated by
turning the headlamps ON (high or low beam) while
the engine is running, turning the ignition switch
OFF, and then turning the headlamp switch OFF
within 45 seconds. The system will not activate if
more than 45 seconds elapse between ignition switch
OFF and headlamp switch OFF. The FCM will allow
the headlamps to remain ON for 60 seconds (config-
urable) before they automatically turn off (If the key
is in the ignition during the headlamp time delay
mode, then the headlamps including panel dimming
will be ON).
LAMP OUTAGE
If one or more of the following lamps (Low and/or
High beams, Brake and/or Turn Signal) are out, then
a ªlamps outº indicator located in the cluster will
illuminate.
OPTICAL HORN/HIGH BEAMS
When the multiplexed multifunction switch is
pulled to the first detent (optical horn) signal, the
headlamps are ON, the Instrument Cluster shall
send a message via J1850 to the FCM to turn on the
headlamps drivers to illuminate all four filaments
(Low and High beams). When the multifunction
switch is pulled to the second detent (high beam) sig-
nal and the headlamps are ON, the Instrument Clus-
ter shall send a message via J1850 to the FCM to
turn on the headlamps drivers. The High Beams are
illuminated and the Low Beams and Fog Lamps (if
ON) are extinguished. If the headlamps were in the
high beam configuration when power was removedfrom the headlamps, the headlamps will return to
their last state prior to being shut off.
DIAGNOSIS AND TESTING - LAMPS/LIGHTING
- EXTERIOR
WARNING: EYE PROTECTION SHOULD BE USED
WHEN SERVICING GLASS COMPONENTS. PER-
SONAL INJURY CAN RESULT.
CAUTION: Do not touch the glass of halogen bulbs
with fingers or other possibly oily surface, reduced
bulb life will result. Do not use bulbs other than
those indicated in the Bulb Application table. Dam-
age to lamp and/or Daytime Running Lamp Module
can result. Do not use fuses, circuit breakers or
relays having greater amperage value than indi-
cated on the fuse panel or in the Owners Manual.
When a vehicle experiences problems with the
headlamp system, verify the condition of the battery
connections, fuses, charging system, headlamp bulbs,
wire connectors, relay, multifunction 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
loose pin connections and corrosion. Repair as neces-
sary.
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.
DRLAMPS/LIGHTING - EXTERIOR 8L - 3
LAMPS/LIGHTING - EXTERIOR (Continued)

(1) Position the front fog lamp relay to the proper
receptacle in the Power Distribution Center (PDC).
(2) Align the front fog lamp relay terminals with
the terminal cavities in the PDC.
(3) Press firmly and evenly on the top of the front
fog lamp relay until the terminals are fully seated in
the PDC.
(4) Reconnect the battery negative cable.
HAZARD SWITCH
DESCRIPTION
The hazard switch is activated by a push button
located in the multifunction switch on the top of the
steering column between the steering wheel and
instrument cluster.
The hazard warning system allows the vehicle
operator to provide other vehicle operators in the
near proximity an optical indication that the vehicle
is disabled or an obstacle to traffic flow. The hazard
warning system has battery voltage at all times,
regardless of ignition position.
OPERATION
The instrument cluster monitors the multiplexed
multifunction switch operation. When the hazard
warning switch is activated, the instrument cluster
will send a J1850 bus message to the Front Control
Module (FCM), then activate the two turn signal
indicators and audible click in the instrument clus-
ter.
The FCM will then activate the necessary relays in
the Power Distribution Center (PDC) to begin flash-
ing both the front and rear turn signal indicator
lamps.
HEADLAMP
REMOVAL
(1) Disconnect and isolate the negitive battery
cable.
(2) Remove the headlamp unit (Refer to 8 - ELEC-
TRICAL/LAMPS/LIGHTING - EXTERIOR/HEAD-
LAMP UNIT - REMOVAL).
(3) Seperate the socket from the headlamp unit.
INSTALLATION
CAUTION: Do Not Touch the bulb glass with fingers
or other oily surfaces. Reduced bulb life will result.
(1) Install the socket into the headlamp unit.
(2) Install the headlamp unit (Refer to 8 - ELEC-
TRICAL/LAMPS/LIGHTING - EXTERIOR/HEAD-
LAMP UNIT - INSTALLATION).(3) Connect the negitive battery cable.
HEADLAMP SWITCH
DESCRIPTION
The multiplexed headlamp switch is located on the
instrument panel. The headlamp switch controls the
parking lamps, fog lamps and the headlamps. A sep-
arate switch in the module controls the interior
lamps and instrument cluster illumination. This
switch also contains a rheostat for controlling the
illumination level of the cluster lamps.
OPERATION
The multiplexed headlamp switch has an off, park-
ing lamp, fog lamp and a headlamp on position. High
beams are controlled by the multiplexed multifunc-
tion switch on the steering column. The fog lamps
are illuminated by pulling back on the headlamp
switch knob when in the parking lamp or headlamp
ON position.The headlamp switch cannot be
repaired. It must be replaced.
The Instrument Cluster monitors the headlamp
and multifunction switch operation. When the head-
lamp switch is rotated to the parking lamp or On
position the Instrument Cluster sends a J1850 mes-
sage to the Front Control Module, which is mated to
the power distribution center to become the Inte-
grated Control Module, to illuminate the appropriate
bulbs. When the multifunction switch is activated to
the optical horn or high beam position the Instru-
ment Cluster illuminates the high beam indicator
and sends a J1850 message to the Front Control
Module to illuminate the appropriate bulbs.
REMOVAL
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. 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.
8L - 14 LAMPS/LIGHTING - EXTERIORDR
FOG LAMP RELAY (Continued)

(3) Install the bolts attaching headlamp unit to the
fender (Fig. 11).
(4) Align the seal and install the push pins.
(5) Connect the battery negative cable.
ADJUSTMENTS
Headlamps can be aligned using the screen method
provided in this section.
LAMP ALIGNMENT SCREEN PREPARATION
(1) Position vehicle on a level surface perpendicu-
lar to a flat wall 7.62 meters (25 ft) away from front
of headlamp lens (Fig. 12).
(2) If necessary, tape a line on the floor 7.62
meters (25 ft) away from and parallel to the wall.
(3) Up 1.27 meters (5 feet) from the floor, tape a
line on the wall at the centerline of the vehicle. Sight
along the centerline of the vehicle (from rear of vehi-
cle forward) to verify accuracy of the line placement.
(4) Rock vehicle side-to-side three times to allow
suspension to stabilize.
(5) Jounce front suspension three times by pushing
downward on front bumper and releasing.
(6) Measure the distance from the center of head-
lamp lens to the floor. Transfer measurement to thealignment screen (with tape). Use this line for
up/down adjustment reference.
(7) Measure distance from the centerline of the
vehicle to the center of each headlamp being aligned.
Transfer measurements to screen (with tape) to each
side of vehicle centerline. Use these lines for left/
right adjustment reference.
VEHICLE PREPARATION FOR HEADLAMP
ALIGNMENT
(1) Verify headlamp dimmer switch and high beam
indicator operation.
(2) Correct defective components that could hinder
proper headlamp alignment.
(3) Verify proper tire inflation.
(4) Clean headlamp lenses.
(5) Verify that luggage area is not heavily loaded.
(6) Fuel tank should be FULL. Add 2.94 kg (6.5
lbs.) of weight over the fuel tank for each estimated
gallon of missing fuel.
HEADLAMP ALIGNMENT
A properly aimed low beam headlamp will project
top edge of high intensity pattern on screen from 50
mm (2 in.) above to 50 mm (2 in.) below headlamp
Fig. 12 Headlamp Alignment Screen - Typical
1 - CENTER OF VEHICLE
2 - CENTER OF HEADLAMP3 - 7.62 METERS (25 FT.)
4 - FRONT OF HEADLAMP
8L - 16 LAMPS/LIGHTING - EXTERIORDR
HEADLAMP UNIT (Continued)