DODGE RAM 2003 Service Repair Manual

HEADLAMP DIAGNOSIS
CONDITION POSSIBLE CAUSES CORRECTION
HEADLAMPS ARE DIM
WITH ENGINE IDLING
OR IGNITION TURNED
OFF1. 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 ground. 6. Test for voltage drop across ground circuits,
refer to Electrical, Wiring Diagram Information.
HEADLAMP BULBS
BURN OUT
FREQUENTLY1. Integrated Control Module (ICM)
not controlling voltage.1. Test and repair Integrated Control Module.
2. Loose or corroded terminals or
splices in circuit.2. Inspect and repair all connectors and splices.
Refer to Electrical, Wiring Information.
HEADLAMPS ARE DIM
WITH ENGINE
RUNNING ABOVE IDLE1. Charging system output too low. 1. Test and repair charging system, refer to
Electrical, Wiring Information.
2. Poor lighting circuit ground. 2. Test for voltage drop across ground circuits,
refer to Electrical, Wiring Information.
3. High resistance in headlamp
circuit.3. Test amperage draw of headlamp circuit.
HEADLAMPS FLASH
RANDOMLY1. Poor lighting circuit ground. 1. Test for voltage drop across ground
locations, refer to Electrical, Wiring Information.
2. Variable resistance in headlamp
circuit.2. Test amperage draw of headlamp circuit.
3. Loose or corroded terminals or
splices in circuit.3. Inspect and repair all connectors and splices,
refer to Electrical, Wiring Information.
4. Faulty headlamp switch. 4. Replace headlamp switch.
5. Front Control Module
Malfunction.5. Refer to appropriate ICM/FCM diagnostics.
8L - 4 LAMPS/LIGHTING - EXTERIORDR
LAMPS/LIGHTING - EXTERIOR (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
HEADLAMPS DO NOT
ILLUMINATE1. No voltage to headlamps. 1. Repair open headlamp circuit, refer to
Electrical, Wiring Information.
2. No ground at headlamps. 2. Repair circuit ground, refer to Electrical,
Wiring Information.
3. Broken connector terminal or
wire splice in headlamp circuit.3. Repair connector terminal or wire splice.
4. Faulty or burned out bulb. 4. Replace headlamp bulb(s).
5. Integrated Control Module
malfunction.5. Refer to appropriate Body Control Module
diagnostics.
6. J1850 Bus Communication 6. Verify messages being transmitted by
Instrument Cluster and received by FCM.
7. Front Control Module
Malfunction.7. Refer to appropriate ICM/FCM diagnostics.
HEADLAMPS ON WITH
IGNITION IN RUN, WITH
HEADLAMP SWITCH
OFF1. Faulty headlamp switch. 1. Replace headlamp switch (review Instrument
Cluster logged faults).
2. Diagnostic tool indicates (4.7 -
5.0V) on headlamp switch input to
Instrument Cluster.2. Inspect and repair terminals, connectors and
open circuits.
3. J1850 Bus Communication. 3. Verify messages being transmitted by
Instrument Cluster and received by FCM.
4. Front Control Module
Malfunction.4. Refer to appropriate ICM/FCM diagnostics.
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 ground. 6. Test for voltage drop across 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.
DRLAMPS/LIGHTING - EXTERIOR 8L - 5
LAMPS/LIGHTING - EXTERIOR (Continued)

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
Back-up 3157
Center High Mounted
Stop lamp912
Fog lamp 9006LL
Front Park/Turn Signal 4157NAK
Head lamp 9007
License Plate 7F69
Tail, Brake, Turn Signal 3157
Side Marker, Tail Gate,
Cab Clearance168
SPECIAL TOOLS - HEADLAMP ALIGNMENT
BACKUP LAMP
REMOVAL
(1) Remove and isolate the negitive battery cable.
(2) Remove the taillamp unit (Refer to 8 - ELEC-
TRICAL/LAMPS/LIGHTING - EXTERIOR/TAIL
LAMP UNIT - REMOVAL).
(3) Remove the bulb back plate from the tail lamp
unit.
(4) Separate the bulb from the socket.
INSTALLATION
(1) Install the bulb into the socket.
(2) Install the bulb back plate to 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.
BACKUP LAMP SWITCH
DESCRIPTION
Vehicles equipped with a manual transmission
have a normally open, spring-loaded plunger type
back-up lamp switch (Fig. 1). 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.
Headlamp Aiming Kit C-4466±A
DRLAMPS/LIGHTING - EXTERIOR 8L - 7
LAMPS/LIGHTING - EXTERIOR (Continued)

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.
BRAKE LAMP
REMOVAL
(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 bulb back plate from the tail lamp
unit.
(4) Remove the bulb from the back plate.
INSTALLATION
(1) Install the bulb into the back plate.
(2) Install the bulb back plate to the tail lamp
unit.
(3) Install the tail lamp unit (Refer to 8 - ELEC-
TRICAL/LAMPS/LIGHTING - EXTERIOR/TAIL
LAMP UNIT - INSTALLATION).
(4) Connect 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. 1 Backup Lamp Switch - Typical
1 - MANUAL TRANSMISSION
2 - BACKUP LAMP SWITCH
3 - ENGINE WIRE HARNESS
8L - 8 LAMPS/LIGHTING - EXTERIORDR
BACKUP LAMP SWITCH (Continued)

Vehicles equipped with the speed control option use
a dual function brake lamp switch. The PCM moni-
tors the state of the dual function brake lamp switch.
The brake switch is equipped with three sets of
contacts, one normally open and the other two nor-
mally closed (brakes disengaged). The PCM sends a
12 volt signal to one of the normally closed contacts
in the brake switch, which is returned to the PCM as
a brake switch state signal. With the contacts closed,
the 12 volt signal is pulled to ground causing the sig-
nal to go low. The low voltage signal, monitored by
the PCM, indicates that the brakes are not applied.
When the brakes are applied, the contacts open,
causing the PCM's output brake signal to go high,
disengaging the speed control, cutting off PCM power
to the speed control solenoids.
The second set of normally closed contacts supplies
12 volts from the PCM any time speed control is
turned on. Through the brake switch, voltage is
routed to the speed control servo solenoids. The
speed control solenoids (vacuum, vent and dump) are
provided this voltage any time the speed control is
ON and the brakes are disengaged.
When the driver applies the brakes, the contacts
open and voltage is interrupted to the solenoids. The
normally open contacts are fed battery voltage. When
the brakes are applied, battery voltage is supplied to
the brake lamps.
The brake lamp switch can only be adjusted once.
That is at the initial installation of the switch. If the
switch is not adjusted properly or has been removed,
a new switch must be installed and adjusted.
DIAGNOSIS AND TESTING - BRAKE LAMP
SWITCH
The brake lamp switch can be tested with an ohm-
meter. The ohmmeter is used to check continuity
between the pin terminals (Fig. 2).
SWITCH CIRCUIT IDENTIFICATION
²Terminals 1 and 2: brake lamp circuit
²Terminals 3 and 4: RWAL/ABS module and Pow-
ertrain Control Module (PCM) circuit
²Terminals 5 and 6: speed control circuit
SWITCH CONTINUITY TEST
NOTE: Disconnect switch harness before testing
switch continuity.
With switch plunger extended, attach test leads to
pins 1 and 2. Replace switch if meter indicates no
continuity.
With switch plunger retracted, attach test leads to
pins 3 and 4. Replace switch if meter indicates no
continuity.With switch plunger retracted, attach test leads to
pins 5 and 6. Replace switch if meter indicates no
continuity.
REMOVAL
(1) Disconnect the switch harness (Fig. 3).
(2) Press and hold the brake pedal in applied posi-
tion.
(3) Rotate the switch counterclockwise about 30É to
align the switch lock tab with the notch in bracket.
(4) Pull the switch rearward out of the mounting
bracket and release the brake pedal.
Fig. 2 Brake Lamp Switch Terminal Identification
1 - TERMINAL PINS
2 - PLUNGER TEST POSITIONS
Fig. 3 Brake Lamp Switch & Bracket
1 - RELEASE LEVER
2 - BRACKET
3 - BRAKE PEDAL SUPPORT
4 - BRAKE LAMP SWITCH
DRLAMPS/LIGHTING - EXTERIOR 8L - 9
BRAKE LAMP SWITCH (Continued)

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. 4).
(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.
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. 5)
Fig. 4 CENTER HIGH MOUNT STOP LAMP Ð
TYPICAL
1 - CHMSL CARGO LAMP HOUSING
2 - CHMSL
3 - CARGO LAMPS
4 - SCREW
5 - CLIP
6 - CAB
8L - 10 LAMPS/LIGHTING - EXTERIORDR
BRAKE LAMP SWITCH (Continued)

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. 6).
(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-
ment of the vehicle. The front fog lamp relay is a
conventional International Standards Organization
Fig. 5 CLEARANCE LAMP
1 - NUT
2 - CAB ROOF
3 - BULB SOCKET
4 - CLEARANCE LAMP
5 - SCREW
6 - BULB
Fig. 6 Fog Lamp
1 - SCREW
2 - FOG LAMP UNIT
3 - CONNECTOR
Fig. 7 ISO Micro Relay
30 - COMMON FEED
85 - COIL GROUND
86 - COIL BATTERY
87 - NORMALLY OPEN
87A - NORMALLY CLOSED
DRLAMPS/LIGHTING - EXTERIOR 8L - 11
CAB CLEARANCE LAMP (Continued)

(ISO) micro relay (Fig. 7). Relays conforming to the
ISO specifications have common physical dimensions,
current capacities, terminal patterns, and terminal
functions. The relay is contained within a small, rect-
angular, molded plastic housing and is connected to
all of the required inputs and outputs by five integral
male spade-type terminals that extend from the bot-
tom of the relay base.
The front fog lamp relay cannot be adjusted or
repaired and, if faulty or damaged, the unit must be
replaced.
OPERATION
The front fog lamp relay is an electromechanical
switch that uses a low current input from the Front
Control Module (FCM) to control a high current out-
put to the front fog lamps. The movable common feed
contact point is held against the fixed normally
closed contact point by spring pressure. When the
relay coil is energized, an electromagnetic field is
produced by the coil windings. This electromagnetic
field draws the movable relay contact point away
from the fixed normally closed contact point, and
holds it against the fixed normally open contact
point. When the relay coil is de-energized, spring
pressure returns the movable contact point back
against the fixed normally closed contact point. A
resistor is connected in parallel with the relay coil in
the relay, and helps to dissipate voltage spikes and
electromagnetic interference that can be generated as
the electromagnetic field of the relay coil collapses.
The front fog lamp relay terminals are connected
to the vehicle electrical system through a connector
receptacle in the Power Distribution Center (PDC).
The inputs and outputs of the front fog lamp relay
include:
²Common Feed Terminal- The common feed
terminal (30) receives battery voltage at all times
from a fuse in the PDC through a fused B(+) circuit.
²Coil Ground Terminal- The coil ground termi-
nal (85) is connected to a control output of the Front
Control Module (FCM) through a front fog lamp relay
control circuit. The FCM controls front fog lamp oper-
ation by controlling a ground path through this cir-
cuit.
²Coil Battery Terminal- The coil battery ter-
minal (86) receives battery voltage at all times from
a fuse in the PDC through a fused B(+) circuit.
²Normally Open Terminal- The normally open
terminal (87) is connected to the front fog lamps
through a front fog lamp relay output circuit and
provides battery voltage to the front fog lamps when-
ever the relay is energized.
²Normally Closed Terminal- The normally
closed terminal (87A) is not connected in this appli-
cation.The front fog lamp relay can be diagnosed using
conventional diagnostic tools and methods.
DIAGNOSIS AND TESTING - FRONT FOG LAMP
RELAY
The front fog lamp relay (Fig. 8) is located in the
Power Distribution Center in the engine compart-
ment. Refer to the appropriate wiring information.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE SUPPLEMENTAL RESTRAINT
SYSTEM BEFORE ATTEMPTING ANY STEERING
WHEEL, STEERING COLUMN, DRIVER AIRBAG,
PASSENGER AIRBAG, SEAT BELT TENSIONER,
FRONT IMPACT SENSORS, SIDE CURTAIN AIRBAG,
OR INSTRUMENT PANEL COMPONENT DIAGNOSIS
OR SERVICE. DISCONNECT AND ISOLATE THE
BATTERY NEGATIVE (GROUND) CABLE, THEN
WAIT TWO MINUTES FOR THE SYSTEM CAPACI-
TOR TO DISCHARGE BEFORE PERFORMING FUR-
THER DIAGNOSIS OR SERVICE. THIS IS THE ONLY
SURE WAY TO DISABLE THE SUPPLEMENTAL
RESTRAINT SYSTEM. FAILURE TO TAKE THE
PROPER PRECAUTIONS COULD RESULT IN ACCI-
DENTAL AIRBAG DEPLOYMENT AND POSSIBLE
PERSONAL INJURY.
(1) Remove the front fog lamp relay from the PDC.
(Refer to 8 - ELECTRICAL/LAMPS/LIGHTING -
EXTERIOR/FRONT FOG LAMP RELAY - REMOV-
AL).
(2) A relay in the de-energized position should
have continuity between terminals 87A and 30, and
no continuity between terminals 87 and 30. If OK, go
to Step 3. If not OK, replace the faulty relay.
Fig. 8 ISO Micro Relay
30 - COMMON FEED
85 - COIL GROUND
86 - COIL BATTERY
87 - NORMALLY OPEN
87A - NORMALLY CLOSED
8L - 12 LAMPS/LIGHTING - EXTERIORDR
FOG LAMP RELAY (Continued)

(3) Resistance between terminals 85 and 86 (elec-
tromagnet) should be 75   8 ohms. If OK, go to Step
4. If not OK, replace the faulty relay.
(4) Connect a battery to terminals 85 and 86.
There should now be continuity between terminals
30 and 87, and no continuity between terminals 87A
and 30. If OK, reinstall the relay and use a DRBIIIt
scan tool to perform further testing. Refer to the
appropriate diagnostic information.
REMOVAL
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE SUPPLEMENTAL RESTRAINT
SYSTEM BEFORE ATTEMPTING ANY STEERING
WHEEL, STEERING COLUMN, DRIVER AIRBAG,
PASSENGER AIRBAG, SEAT BELT TENSIONER,
FRONT IMPACT SENSORS, SIDE CURTAIN AIRBAG,
OR INSTRUMENT PANEL COMPONENT DIAGNOSIS
OR SERVICE. DISCONNECT AND ISOLATE THE
BATTERY NEGATIVE (GROUND) CABLE, THEN
WAIT TWO MINUTES FOR THE SYSTEM CAPACI-
TOR TO DISCHARGE BEFORE PERFORMING FUR-
THER DIAGNOSIS OR SERVICE. THIS IS THE ONLY
SURE WAY TO DISABLE THE SUPPLEMENTAL
RESTRAINT SYSTEM. FAILURE TO TAKE THE
PROPER PRECAUTIONS COULD RESULT IN ACCI-
DENTAL AIRBAG DEPLOYMENT AND POSSIBLE
PERSONAL INJURY.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the cover for the Power Distribution
Center (PDC).
(3) Remove the front fog lamp relay by grasping it
firmly and pulling it straight out from the receptacle
in the PDC.
INSTALLATION
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE SUPPLEMENTAL RESTRAINT
SYSTEM BEFORE ATTEMPTING ANY STEERING
WHEEL, STEERING COLUMN, DRIVER AIRBAG,
PASSENGER AIRBAG, SEAT BELT TENSIONER,
FRONT IMPACT SENSORS, SIDE CURTAIN AIRBAG,
OR INSTRUMENT PANEL COMPONENT DIAGNOSIS
OR SERVICE. DISCONNECT AND ISOLATE THE
BATTERY NEGATIVE (GROUND) CABLE, THEN
WAIT TWO MINUTES FOR THE SYSTEM CAPACI-
TOR TO DISCHARGE BEFORE PERFORMING FUR-
THER DIAGNOSIS OR SERVICE. THIS IS THE ONLY
SURE WAY TO DISABLE THE SUPPLEMENTAL
RESTRAINT SYSTEM. FAILURE TO TAKE THE
PROPER PRECAUTIONS COULD RESULT IN ACCI-
DENTAL AIRBAG DEPLOYMENT AND POSSIBLE
PERSONAL INJURY.(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 indi-
cators and audible click in the instrument cluster.
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.
DRLAMPS/LIGHTING - EXTERIOR 8L - 13
FOG LAMP RELAY (Continued)