bulb DODGE RAM 1500 1998 2.G Service Manual

CONDITION POSSIBLE CAUSES CORRECTION
FOG LAMPS ARE DIM
WITH ENGINE
RUNNING ABOVE IDLE1. Charging system output too low. 1. Test and repair charging system. Refer to
Electrical, Charging.
2. Poor lighting circuit ground. 2. Test for voltage drop across ground
locations. Refer to Electrical, Wiring
Information.
3. High resistance in fog lamp
circuit.3. Test amperage draw of fog lamp circuit.
FOG LAMPS FLASH
RANDOMLY1. Poor lighting circuit ground. 1. Test for voltage drop across ground
locations. Refer to Electrical, Wiring
Information.
2. Variable resistance in fog lamp
circuit.2. Test amperage draw of fog lamp circuit.
3. Faulty fog lamp switch (part of
headlamp switch).3. Replace headlamp switch.
4. Loose or corroded terminals or
splices in circuit.4. Inspect and repair all connectors and splices.
Refer to Electrical, Wiring Information.
5. Is relay engaging properly? 5. Verify function of fog lamp relay in IPM.
6. J1850 Bus Communication. 6. Verify J1850 message (fog lamp info)
transmitted from Instrument Cluster and
received by FCM.
FOG LAMPS DO NOT
ILLUMINATE1. Blown fuse for fog lamp. 1. Replace fuse. Refer to Electrical, Wiring
Information.
2. No ground at fog lamps. 2. Repair circuit ground. Refer to Electrical,
Wiring Information.
3. Faulty fog lamp switch (part of
headlamp switch).3. Replace headlamp switch.
4. Broken connector terminal or
wire splice in fog lamp circuit.4. Repair connector terminal or wire splice.
5. Faulty or burned out bulb. 5. Replace bulb.
6. Is relay engaging? 6. Verify function of fog lamp relay in IPM.
7. J1850 Bus Communication. 7. Verify J1850 message (fog lamp info)
transmitted from Instrument Cluster and
received by FCM.
DAYTIME RUNNING LAMP (CANADA ONLY) DIAGNOSIS
CONDITION POSSIBLE CAUSES CORRECTION
DAYTIME RUNNING
LAMPS DO NOT
OPERATE1. Parking brake engaged. 1. Disengage parking brake.
2. Parking brake circuit shorted
to ground.2. Check cluster telltale, refer to the appropriate
wiring information.
3. Headlamp circuit shorted to
ground.3. Refer to the appropriate wiring information.
4. FCM, Instrument Cluster not
programed with Canadian
country code.4. Check country code.
8L - 6 LAMPS/LIGHTING - EXTERIORDR
LAMPS/LIGHTING - EXTERIOR (Continued)

STANDARD PROCEDURE
SAFETY PRECAUTIONS
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 with higher
candle power than indicated in the Bulb Application
table . Damage to lamp and/or Daytime Running
Lamp Module can result.Do not use fuses, circuit
breakers or relays having greater amperage value
than indicated on the fuse panel or in the Owners
Manual.
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.
SPECIFICATIONS
EXTERIOR LAMPS
CAUTION: Do not use bulbs that have a higher can-
dle power than the bulb listed in the Bulb Applica-
tion Table. Damage to lamp can result. Do not touch
halogen bulbs with fingers or other oily surfaces.
Bulb life will be reduced.
The following Bulb Application Table lists the lamp
title on the left side of the column and trade number
or part number on the right.
BULB APPLICATION TABLE
LAMP BULB
Backup - w/cargo box 3057
Backup - w/box off 1156
Center High Mounted
Stop lamp912
Fog lamp 9006LL
Front Park/Turn Signal 3157NA
Head lamp 9007
License Plate 168
Tail, Brake, Turn Signal -
w/cargo box3057
LAMP BULB
Tail, Brake, Turn Signal -
w/box off1157
Side Marker, Tail Gate,
Cab Clearance168
BACKUP LAMP
REMOVAL
REMOVAL - WITH CARGO BOX
(1) Remove and isolate the negative battery cable.
(2) Remove the taillamp unit (Refer to 8 - ELEC-
TRICAL/LAMPS/LIGHTING - EXTERIOR/TAIL
LAMP UNIT - REMOVAL).
(3) Remove the lamp back plate from the tail lamp
unit.
(4) Release the backup lamp bulb locking tabs and
remove the bulb from the back plate.
REMOVAL - WITHOUT CARGO BOX
(1) Disconnect and isolate the negative battery
cable.
(2) Remove the four screws that secure the tail
lamp lens to the tail lamp housing (Fig. 1).
(3) Separate the tail lamp lens from the tail lamp
housing.
(4) Push the backup lamp bulb inward and rotate
it counter-clockwise.
(5) Remove the backup lamp bulb from the backup
lamp socket.
INSTALLATION
INSTALLATION - WITH CARGO BOX
(1) Install the backup lamp bulb into the lamp
back plate.
Fig. 1 Tail Lamp Lens
DRLAMPS/LIGHTING - EXTERIOR 8L - 7
LAMPS/LIGHTING - EXTERIOR (Continued)

(2) Install the lamp back plate onto the tail lamp
unit.
(3) Install the tail lamp unit (Refer to 8 - ELEC-
TRICAL/LAMPS/LIGHTING - EXTERIOR/TAIL
LAMP UNIT - INSTALLATION).
(4) Reconnect the negative battery cable.
INSTALLATION - WITHOUT CARGO BOX
(1) Install the backup lamp bulb into the backup
lamp socket by pushing inward and rotating it clock-
wise.
NOTE: Install the tail lamp lens with the clear por-
tion (back-up lens) at the top of the housing. Make
sure that the gasket is correctly in place and not
twisted or torn.
(2) Position the tail lamp lens and gasket onto the
tail lamp unit.
NOTE: Do not overtighten the tail lamp lens screws
or damage to the tail lamp lens may result.
(3) Install the four screws that secure the tail
lamp lens to the tail lamp unit. Tighten the screws
securely.
(4) Reconnect the negative battery cable.
BACKUP LAMP SWITCH
DESCRIPTION
Vehicles equipped with a manual transmission
have a normally open, spring-loaded plunger typeback-up lamp switch (Fig. 2). The backup lamp
switch is located in a threaded hole on the side of the
manual transmission housing. The backup lamp
switch has a threaded body and a hex formation near
the plunger end of the switch, and an integral con-
nector at the opposite end of the switch. When
installed, only the connector and the hex formation
are visible on the outside of the transmission hous-
ing. Vehicles with an optional electronic automatic
transmission have a Transmission Range Sensor
(TRS) that is used to perform several functions,
including that of the backup lamp switch. The TRS is
described in further detail elsewhere in this service
information. The backup lamp switch cannot be
adjusted or repaired and, if faulty or damaged, the
entire switch unit must be replaced.
OPERATION
The backup lamp switch controls the flow of bat-
tery voltage to the backup lamp bulbs through an
output on the back-up lamp feed circuit. The switch
plunger is mechanically actuated by the gearshift
mechanism within the transmission, which will
depress the switch plunger and close the switch con-
tacts whenever the reverse gear has been selected.
The switch receives battery voltage through a fuse in
the Integrated Power Module (IPM) on a fused igni-
tion switch output (run) circuit whenever the ignition
switch is in the On position. A take out of the engine
wire harness connects the backup lamp switch to the
vehicle electrical system. The backup lamp switch
and circuits can be tested using conventional diag-
nostic tools and methods.
DIAGNOSIS AND TESTING - BACKUP LAMP
SWITCH
(1) Disconnect and isolate the battery negative
cable.
(2) Raise and support the vehicle.
(3) Locate and disconnect the engine wire harness
connector for the backup lamp switch.
(4) Check for continuity between the two terminal
pins in the backup lamp switch connector.
(a) With the gear selector lever in the Reverse
position, there should be continuity.
(b) With the gear selector lever in any position
other than Reverse, there should be no continuity.
Fig. 2 Backup Lamp Switch - Typical
1 - MANUAL TRANSMISSION
2 - BACKUP LAMP SWITCH
3 - ENGINE WIRE HARNESS
8L - 8 LAMPS/LIGHTING - EXTERIORDR
BACKUP LAMP (Continued)

BRAKE LAMP
REMOVAL
REMOVAL - WITH CARGO BOX
(1) Disconnect and isolate the negative battery
cable.
(2) Remove the tail lamp unit (Refer to 8 - ELEC-
TRICAL/LAMPS/LIGHTING - EXTERIOR/TAIL
LAMP UNIT - REMOVAL).
(3) Remove the lamp back plate from the tail lamp
unit.
(4) Release the brake lamp bulb locking tabs and
remove the bulb from the back plate.
REMOVAL - WITHOUT CARGO BOX
(1) Disconnect and isolate the negative battery
cable.
(2) Remove the four screws that secure the tail
lamp lens to the tail lamp housing (Fig. 3).
(3) Separate the tail lamp lens from the tail lamp
housing.
(4) Push the brake lamp bulb inward and rotate it
counter-clockwise.
(5) Remove the brake lamp bulb from the brake
lamp socket.
INSTALLATION
INSTALLATION - WITH CARGO BOX
(1) Install the brake lamp bulb into the lamp back
plate.
(2) Install the lamp back plate onto the tail lamp
unit.
(3) Install the tail lamp unit (Refer to 8 - ELEC-
TRICAL/LAMPS/LIGHTING - EXTERIOR/TAIL
LAMP UNIT - INSTALLATION).
(4) Reconnect the negative battery cable.
INSTALLATION - WITHOUT CARGO BOX
(1) Install the brake lamp bulb into the brake
lamp socket by pushing inward and rotating it clock-
wise.
NOTE: Install the tail lamp lens with the clear por-
tion (back-up lens) at the top of the housing. Make
sure that the gasket is correctly in place and not
twisted or torn.
(2) Position the tail lamp lens and gasket onto the
tail lamp unit.
NOTE: Do not overtighten the tail lamp lens screws
or damage to the tail lamp lens may result.
(3) Install the four screws that secure the tail
lamp lens to the tail lamp unit. Tighten the screws
securely.
(4) Reconnect the negative battery cable.
BRAKE LAMP SWITCH
DESCRIPTION
The plunger type brake lamp switch is mounted on
a bracket attached to the base of the steering col-
umn, under the instrument panel.
CAUTION: The switch can only be adjusted during
initial installation. If the switch is not adjusted prop-
erly a new switch must be installed.
OPERATION
The brake lamp switch is hard wired to the Center
High Mount Stop Lamp (CHMSL) and also moni-
tored by the Instrument Cluster for use by the brake
lamp, speed control brake sensor circuits and elec-
tronic brake distribution (EBD). The brake lamp cir-
cuit is open until the plunger is depressed. The speed
control and brake sensor circuits are closed until the
plunger is depressed. When the brake lamp switch
transitions, the CHMSL transitions and instrument
cluster transmits a brake applied/released message
on the bus. The Integrated Power Module (IPM) will
then transition the brake lamps.
When the brake light switch is activated, the Pow-
ertrain Control Module (PCM) receives an input indi-
cating that the brakes are being applied. After
receiving this input, the PCM maintains idle speed to
a scheduled rpm through control of the Idle Air Con-
trol (IAC) motor. The brake switch input is also used
to disable vent and vacuum solenoid output signals
to the speed control servo.
Fig. 3 Tail Lamp Lens
DRLAMPS/LIGHTING - EXTERIOR 8L - 9

INSTALLATION
(1) Press and hold the brake pedal down.
(2) Align the tab on thenewswitch with the notch
in the switch bracket. Insert the switch in the
bracket and turn it clockwise about 30É to lock it in
place.
(3) Connect the harness wires to the switch.
(4) Release the brake pedal.
(5) Move the release lever on the switch parallel
with the connector to engage the switch plunger. The
switch is now adjusted andcan notbe adjusted
again.
CENTER HIGH MOUNTED
STOP LAMP
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the CHMSL from the roof panel. Refer
to (Refer to 8 - ELECTRICAL/LAMPS/LIGHTING -
EXTERIOR/CENTER HIGH MOUNTED STOP
LAMP UN - REMOVAL).
(3) Turn the bulb socket 1/4 turn counterclockwise.
(4) Separate the socket from the lamp.
(5) Remove the bulb.
INSTALLATION
(1) Position the bulb in the socket and press into
place.
(2) Position the socket in the lamp.
(3) Turn the bulb socket 1/4 turn clockwise.
(4) Install the CHMSL. Refer to (Refer to 8 -
ELECTRICAL/LAMPS/LIGHTING - EXTERIOR/
CENTER HIGH MOUNTED STOP LAMP UN -
INSTALLATION).
(5) Connect the battery negative cable.
CENTER HIGH MOUNTED
STOP LAMP UNIT
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove screws holding CHMSL to roof panel
(Fig. 6).(3) Separate CHMSL from roof.
(4) Disengage wire connector from body wire har-
ness.
(5) Separate CHMSL from vehicle.
INSTALLATION
(1) Position lamp at cab roof and connect wire con-
nector.
(2) Install screws holding CHMSL to roof panel.
Tighten securely.
(3) Connect the battery negative cable.
CAB CLEARANCE LAMP
REMOVAL
(1) Remove both retaining screws and separate the
lamp from the roof.
(2) Quarter turn counter clockwise to separate
bulb socket from lamp.
Fig. 6 Center High Mount Stop Lamp - Typical
1 - CHMSL CARGO LAMP HOUSING
2 - CHMSL
3 - CARGO LAMPS
4 - SCREW
5 - CLIP
6 - CAB
DRLAMPS/LIGHTING - EXTERIOR 8L - 11
BRAKE LAMP SWITCH (Continued)

INSTALLATION
(1) Quarter twist the bulb socket clockwise into
the lamp housing.
(2) Position the lamp assembly onto the roof and
install retaining screws. (Fig. 7)
FOG LAMP
REMOVAL
NOTE: The fog lamps are serviced from the rear-
ward side of the front bumper.
(1) Disconnect and isolate the battery negative
cable.
(2) Disengage fog lamp harness connector.
(3) Remove the bolts attaching the fog lamp to the
bumper (Fig. 8).
(4) Separate fog lamp from bumper.
INSTALLATION
(1) Position fog lamp in bumper.
(2) Install the bolts attaching the fog lamp to the
bumper.
(3) Connect fog lamp harness connector.
(4) Connect the battery negative cable.(5) Check for proper operation and beam align-
ment.
FOG LAMP RELAY
DESCRIPTION
The front fog lamp relay is located in the Power
Distribution Center (PDC) in the engine compart-
Fig. 7 Clearance Lamp
1 - NUT
2 - CAB ROOF
3 - BULB SOCKET
4 - CLEARANCE LAMP
5 - SCREW
6 - BULB
Fig. 8 Fog Lamp
1 - SCREW
2 - FOG LAMP UNIT
3 - CONNECTOR
Fig. 9 ISO Micro Relay
30 - COMMON FEED
85 - COIL GROUND
86 - COIL BATTERY
87 - NORMALLY OPEN
87A - NORMALLY CLOSED
8L - 12 LAMPS/LIGHTING - EXTERIORDR
CAB CLEARANCE LAMP (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)

(2) Remove the left instrument panel bezel. (Refer
to 23 - BODY/INSTRUMENT PANEL/CLUSTER
BEZEL - REMOVAL).
(3) Disconnect the harness connector.
(4) Remove the screws that secure the headlamp
switch to the instrument panel bezel (Fig. 10).
(5) Remove the headlamp switch from the instru-
ment panel bezel.
INSTALLATION
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) Position the headlamp switch to the left instru-
ment panel bezal and secure with screws.Tighten the
screws to 2.2 N´m (20 in. lbs.).(2) Reconnect the instrument panel wire harness
connector for the headlamp switch.
(3) Position the left instrument panel bezal on to
the instrument panel.
(4) Install the cluster bezel onto the instrument
panel (Fig. 10).
(5) Connect the battery negative cable.
HEADLAMP UNIT
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the push pins attaching the seal to the
fender.
(3) Remove the bolts attaching the headlamp unit
to the fender (Fig. 11).
(4) Remove the bulb sockets from the headlamp
unit
(5) Separate headlamp unit from vehicle.
INSTALLATION
CAUTION: Do not touch the bulb glass with fingers
or other oily surfaces. Reduced bulb life will result.
(1) Install the bulb sockets for the front park/turn
signal and headlamp.
(2) Position headlamp unit in inner fender panel.
Fig. 10 Headlamp Switch Removal
1 - DASH BOARD
2 - HEADLAMP SWITCH
3 - INSTRUMENT PANEL BEZAL
Fig. 11 Headlamp - Typical
1 - SEAL
2 - PUSH PIN
3 - SCREW
4 - HEADLAMP UNIT
DRLAMPS/LIGHTING - EXTERIOR 8L - 15
HEADLAMP SWITCH (Continued)

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

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