2002 JEEP LIBERTY low beam

stant battery voltage is supplied to the flasher so that it
can perform the hazard warning function, and ignition
switched battery voltage is supplied for the turn signal
function. The Integrated Circuit (IC) within the combi-
nation flasher contains the logic that controls the
flasher operation and the flash rate. The IC receives
separate sense ground inputs from the multi-function
switch for the right and left turn signals, and from the
hazard switch contacts or the BCM for the hazard
warning signals. A special design feature of the combi-
nation flasher allows it to9sense9that a turn signal cir-
cuit or bulb is not operating, and provide the driver an
indication of the condition by flashing the remaining
bulbs in the affected circuit at a higher rate (120 flash-
es-per-minute or higher). Conventional flashers either
continue flashing at their typical rate (heavy-duty type),
or discontinue flashing the affected circuit entirely
(standard-duty type).
Because of the active electronic elements within
the combination flasher, it cannot be tested with con-
ventional automotive electrical test equipment. If the
combination flasher is believed to be faulty, test the
turn signal and hazard warning system. Then
replace the hazard switch with a known good unit to
confirm system operation.
DAYTIME RUNNING LAMP
RELAY
DESCRIPTION
The Daytime Running Lamp (DRL) relay (Fig. 8) is
a solid state relay that is used only on vehicles man-
ufactured for sale in Canada. The DRL relay features
a die cast aluminum housing with integral cooling
fins that act as a heat sink for the solid state DRL
circuitry. Four male spade terminals extend from the
base of the relay through a potting material that
encloses and protects the DRL circuitry. Although the
DRL relay has four terminals that are laid out in a
footprint that is similar to that of a conventional
International Standards Organization (ISO) relay, a
standard ISO relay should never be installed in place
of the DRL relay. The DRL relay is installed in the
Junction Block (JB) on the driver side outboard end
of the instrument panel. Vehicles equipped with this
relay do not have a headlamp high beam relay
installed in the JB.
The DRL relay cannot be adjusted or repaired and,
if faulty or damaged, the unit must be replaced.
OPERATION
The Daytime Running Lamp (DRL) relay is a solid
state relay that controls the flow of battery current
to the high beam filaments of both headlamp bulbs
based upon a duty cycled control input received from
the Body Control Module (BCM) of vehicles equipped
with the DRL feature. By cycling the DRL relay out-
put, the BCM controls the illumination intensity of
the high beam filaments. The DRL relay terminals
are connected to the vehicle electrical system through
a connector receptacle in the Junction Block (JB).
The inputs and outputs of the DRL relay include:
²Battery Current Input- The DRL relay
receives battery current on a fused B(+) circuit from
a fuse in the Power Distribution Center (PDC).
²Ground Input- The DRL relay receives a path
to ground through a splice block located in the
instrument panel wire harness with an eyelet termi-
nal connector that is secured by a nut to a ground
stud on the driver side instrument panel end bracket
near the Junction Block (JB).
²Control Input- The DRL relay control input is
received from the BCM and/or the momentary optical
horn (flash-to-pass) output of the multi-function
switch through a high beam relay control circuit.
²Control Output- The DRL relay supplies bat-
tery current output to the headlamp high beam fila-
ments through the high beam relay output circuit.
Because of active electronic elements within the
DRL relay, it cannot be tested with conventional
automotive electrical test equipment. If the DRL
relay is believed to be faulty, replace the relay with a
known good unit to confirm system operation.
Fig. 8 Daytime Running Lamp Relay
1 - DRL RELAY
2 - HEAT SINK
3 - POTTING MATERIAL
4 - TERMINAL (4)
8L - 20 LAMPS/LIGHTING - EXTERIORKJ
COMBINATION FLASHER (Continued)

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 end cap from the driver side out-
board end of the instrument panel. (Refer to 23 -
BODY/INSTRUMENT PANEL/INSTRUMENT
PANEL END CAP - REMOVAL).
(3) Remove the Daytime Running Lamp (DRL)
relay by grasping it firmly and pulling it straight out
from the receptacle in the Junction Block (JB) (Fig.
9).
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 Daytime Running Lamp (DRL)
relay to the proper receptacle in the Junction Block
(JB) (Fig. 9).
(2) Align the DRL relay terminals with the termi-
nal cavities in the JB receptacle.
(3) Push firmly and evenly on the top of the DRL
relay until the terminals are fully seated in the ter-
minal cavities in the JB receptacle.
(4) Reinstall the end cap onto the driver side out-
board end of the instrument panel. (Refer to 23 -
BODY/INSTRUMENT PANEL/INSTRUMENT
PANEL END CAP - INSTALLATION).
(5) Reconnect the battery negative cable.
FRONT FOG LAMP BULB
REMOVAL
(1) Turn the front wheels full lock in the direction
of the fog lamp bulb that is to be changed.
(2) Disconnect and isolate the battery negative
cable.
(3) Reach into the front wheel opening to unsnap
and lift the cover over the access hole at the front of
the front wheelhouse splash shield (Fig. 10).
(4) Reach through the access hole and firmly grasp
the socket on the back of the front fog lamp unit
housing.
(5) Rotate the socket on the back of the front fog
lamp unit housing counterclockwise about 30
degrees.
CAUTION: Do not contaminate the bulb glass by
touching it with your fingers or by allowing it to
contact other oily surfaces. Shortened bulb life will
result.
Fig. 9 Junction Block - Outboard Side (RHD Shown
- Rotate 180É for LHD)
1 - JB/BCM CONNECTOR
2 - HIGH BEAM RELAY
3 - DRL RELAY
KJLAMPS/LIGHTING - EXTERIOR 8L - 21
DAYTIME RUNNING LAMP RELAY (Continued)

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 steering column opening cover
from the instrument panel. (Refer to 23 - BODY/IN-
STRUMENT PANEL/STEERING COLUMN OPEN-
ING COVER - REMOVAL).
(3) Remove the front fog lamp relay by grasping it
firmly and pulling it straight out from the receptacle
in the Junction Block (JB) (Fig. 13).
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 Junction Block (JB) (Fig. 13).
(2) Align the front fog lamp relay terminals with
the terminal cavities in the JB receptacle.
(3) Push firmly and evenly on the top of the front
fog lamp relay until the terminals are fully seated in
the terminal cavities in the JB receptacle.
(4) Reinstall the steering column opening cover
onto the instrument panel. (Refer to 23 - BODY/IN-
STRUMENT PANEL/STEERING COLUMN OPEN-
ING COVER - INSTALLATION).
(5) Reconnect the battery negative cable.
Fig. 13 Junction Block - Inboard Side (LHD Shown -
Rotate 180É for RHD)
1 - PASSENGER DOOR UNLOCK RELAY
2 - JB C3 CONNECTOR RECEPTACLE
3 - LOW BEAM RELAY
4 - CIRCUIT BREAKER #1
5 - CIRCUIT BREAKER #2
6 - CIRCUIT BREAKER #3
7 - DOOR LOCK RELAY
8 - DEFOGGER RELAY
9-SPARE
10 - FRONT FOG LAMP RELAY
11 - HORN RELAY
12 - SPARE
13 - SPARE
14 - REAR FOG LAMP RELAY
15 - PARK LAMP RELAY
16 - DRIVER DOOR UNLOCK RELAY
17 - JB C1 CONNECTOR RECEPTACLE
18 - JB C2 CONNECTOR RECEPTACLE
8L - 24 LAMPS/LIGHTING - EXTERIORKJ
FRONT FOG LAMP RELAY (Continued)

(1) Position the vehicle on a level surface perpen-
dicular to a flat wall 7.62 meters (25 feet) away from
the front of the front fog lamp lens (Fig. 16). If nec-
essary, tape a line on the floor 7.62 meters (25 feet)
away from and parallel to the wall.
(2) Measure up on the wall 1.27 meters (5 feet)
from the floor and tape a vertical line on the align-
ment screen at the centerline of the vehicle. Sight
along the centerline of the vehicle (from the rear of
the vehicle forward) to verify the accuracy of the cen-
terline placement.
(3) Rock the vehicle from side-to-side three times
to allow the suspension to stabilize, then jounce the
front suspension three times by pushing downward
on the front bumper and releasing. Measure the dis-
tance from the center of the front fog lamp lens to
the floor. Transfer this measurement to the align-
ment screen and tape a horizontal line on the wall at
this mark. This line will be used for up-and-down
adjustment reference.
(4) Measure the distance from the centerline of the
vehicle to the center of each front fog lamp beingaligned. Transfer these measurements to the align-
ment screen and tape a vertical line this distance to
each side of the vehicle centerline. These lines will be
used for left/right reference.
(5) Rotate the front fog lamp adjusting screws to
adjust the beam height as required (Fig. 17).
FRONT LAMP BULB
REMOVAL
The front lamp unit may contain either one or two
bulbs, depending upon the market for which the
vehicle was manufactured. The service procedures for
one bulb or for both bulbs is the same, only the bulb
sizes and types may differ. Be certain any removed
bulb is replaced with the same bulb size and type
that was removed.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the front lamp unit from the front
bumper fascia. (Refer to 8 - ELECTRICAL/LAMPS/
Fig. 16 Front Fog Lamp Alignment - Typical
1 - VEHICLE CENTERLINE
2 - CENTER OF VEHICLE TO CENTER OF FOG LAMP LENS
3 - HIGH-INTENSITY AREA
4 - FLOOR TO CENTER OF FOG LAMP LENS5 - 100 MILLIMETERS (4 INCHES)
6 - 7.62 METERS (25 FEET)
7 - FRONT OF FOG LAMP
8L - 26 LAMPS/LIGHTING - EXTERIORKJ
FRONT FOG LAMP UNIT (Continued)

(3) Pinch the two hooked ends of the wire head-
lamp bulb retainer clip together and engage them
into the slots in the flange of the reflector (Fig. 26).
(4) Position the center opening of the boot seal
over the base of the headlamp bulb and pull it down-
ward until the seal is fully engaged over the bulb
base (Fig. 25).
(5) Position the outer circumference of the boot
seal over the flange on the back of the headlamp unit
housing and pull it downward until the seal is fully
engaged over the flange.
(6) Reinstall the headlamp unit onto the grille
opening reinforcement. (Refer to 8 - ELECTRICAL/
LAMPS/LIGHTING - EXTERIOR/HEADLAMP UNIT
- INSTALLATION).
(7) Reconnect the battery negative cable.
(8) Confirm proper headlamp unit alignment.
(Refer to 8 - ELECTRICAL/LAMPS/LIGHTING -
EXTERIOR/HEADLAMP UNIT - ADJUSTMENTS).
HEADLAMP HIGH BEAM
RELAY
DESCRIPTION
The headlamp high beam relay is located in the
Junction Block (JB) on the driver side outboard end
of the instrument panel in the passenger compart-
ment of the vehicle. The headlamp high beam relay
is omitted from vehicles manufactured for sale in
Canada, which have a Daytime Running Lamp (DRL)
solid state relay installed in the JB that also per-forms the function of the headlamp high beam relay.
The headlamp high beam relay is a conventional
International Standards Organization (ISO) micro
relay (Fig. 28). Relays conforming to the ISO specifi-
cations have common physical dimensions, current
capacities, terminal patterns, and terminal functions.
The relay is contained within a small, rectangular,
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 bottom of
the relay base.
The headlamp high beam relay cannot be adjusted
or repaired and, if faulty or damaged, the unit must
be replaced.
OPERATION
The headlamp high beam relay is an electrome-
chanical switch that uses a low current input from
the Body Control Module (BCM) to control a high
current output to the headlamp high beam filaments.
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 wind-
ings. 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 volt-
age spikes and electromagnetic interference that can
be generated as the electromagnetic field of the relay
coil collapses.
The headlamp high beam relay terminals are con-
nected to the vehicle electrical system through a con-
nector receptacle in the Junction Block (JB). The
inputs and outputs of the headlamp high beam relay
include:
²Common Feed Terminal- The common feed
terminal (30) receives battery current at all times
from a fuse in the Power Distribution Center (PDC)
through a fused B(+) circuit.
²Coil Ground Terminal- The coil ground termi-
nal (85) receives battery current at all times from a
fuse in the PDC through a fused B(+) circuit.
²Coil Battery Terminal- The coil battery ter-
minal (86) is connected to a control output of the
Body Control Module (BCM) and to the momentary
optical horn (flash-to-pass) output of the multi-func-
tion switch through a high beam relay control circuit.
The BCM and/or the multi-function switch controls
headlamp high beam operation by controlling a
ground path through this circuit.
Fig. 28 ISO Micro Relay
30 - COMMON FEED
85 - COIL GROUND
86 - COIL BATTERY
87 - NORMALLY OPEN
87A - NORMALLY CLOSED
KJLAMPS/LIGHTING - EXTERIOR 8L - 33
HEADLAMP BULB (Continued)

the center of the headlamp reflector and thoroughly
clean any fingerprints from the reflector.
(6) Push the mounting flange of the headlamp lev-
eling motor into the mounting hole on the back of
headlamp unit housing unit the motor is firmly
seated (Fig. 32).
(7) Rotate the headlamp leveling motor on the
back of the headlamp unit housing clockwise about
30 degrees.
(8) Reinstall the headlamp bulb into the headlamp
unit housing. (Refer to 8 - ELECTRICAL/LAMPS/
LIGHTING - EXTERIOR/HEADLAMP BULB -
INSTALLATION).
(9) Reconnect the battery negative cable.
HEADLAMP LEVELING
SWITCH
DESCRIPTION
The headlamp leveling switch (Fig. 34) is used only
on vehicles manufactured for certain markets where
the headlamp leveling system is required. The head-
lamp leveling switch is mounted in the driver side
inboard trim bezel on the instrument panel, where it
is secured by molded latch features that are integral
to the switch housing. Only the switch bezel and
thumbwheel are visible on the outer surface of the
instrument panel trim bezel. The black plastic switch
thumbwheel is marked with white numbers ª0,º ª1,º
ª2,º and ª3,º each of which indicates one of the four
switch detent positions. Each higher number repre-sents a lower aiming position of the headlamp beam
relative to the road surface. The black, molded plas-
tic switch housing has an integral connector recepta-
cle on the back, a single latch feature on the top, and
two latch features (one on each side) on the bottom.
The switch is connected to the vehicle electrical sys-
tem through a dedicated take out and connector of
the instrument panel wire harness. Within the
switch housing is the leveling switch circuitry includ-
ing the switch contacts and a series resistor configu-
ration.
The headlamp leveling switch cannot be adjusted
or repaired and, if faulty or damaged, the unit must
be replaced.
OPERATION
The headlamp leveling switch receives battery cur-
rent on a fused park lamp relay output circuit from a
fuse in the Junction Block (JB) whenever the park
lamp relay is energized (park lamps are turned On).
The switch receives a path to ground through a splice
block located in the instrument panel wire harness
with an eyelet terminal connector that is secured by
a nut to a ground stud on the driver side instrument
panel end bracket near the JB. The only output from
the switch is a voltage signal that it provides to the
headlamp leveling motors on a headlamp adjust sig-
nal circuit. Each switch position selects a different
tap on a series resistor within the switch to provide a
different voltage signal to the leveling motors. The
higher the switch position number, the higher the
output voltage level.
The headlamp leveling switch can be tested using
conventional diagnostic tools and methods.
DIAGNOSIS AND TESTING - HEADLAMP
LEVELING SWITCH
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.
Fig. 34 Headlamp Leveling Switch
1 - SWITCH
2 - UPPER LATCH FEATURE (1)
3 - CONNECTOR RECEPTACLE
4 - LOWER LATCH FEATURE (2)
5 - THUMBWHEEL
KJLAMPS/LIGHTING - EXTERIOR 8L - 37
HEADLAMP LEVELING MOTOR (Continued)

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) From the face of the driver side inboard bezel,
align the headlamp leveling switch housing to the
mounting hole in the bezel (Fig. 36).
(2) Push the headlamp leveling switch into the
mounting hole until it is fully seated and the upper
latch and two lower latch features on the switch
housing are engaged on the back of the bezel.
(3) Position the switch and bezel unit to the
instrument panel.
(4) Reconnect the instrument panel wire harness
connector for the headlamp leveling switch to the
switch connector receptacle.
(5) Reinstall the driver side inboard bezel onto the
instrument panel. (Refer to 23 - BODY/INSTRU-
MENT PANEL/INSTRUMENT PANEL DRIVER
SIDE BEZEL - INSTALLATION).
(6) Reconnect the battery negative cable.
HEADLAMP LOW BEAM RELAY
DESCRIPTION
The headlamp low beam relay is located in the
Junction Block (JB) below the driver side outboard
end of the instrument panel in the passenger com-
partment of the vehicle. The headlamp low beam
relay is a conventional International Standards
Organization (ISO) micro relay (Fig. 37). Relays con-
forming to the ISO specifications have common phys-
ical dimensions, current capacities, terminal
patterns, and terminal functions. The relay is con-
tained within a small, rectangular, molded plastic
housing and is connected to all of the required inputs
and outputs by five integral male spade-type termi-
nals that extend from the bottom of the relay base.
The headlamp low beam relay cannot be adjusted
or repaired and, if faulty or damaged, the unit must
be replaced.
OPERATION
The headlamp low beam relay is an electromechan-
ical switch that uses a low current input from the
Body Control Module (BCM) to control a high current
output to the headlamp low beam filaments. 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 electro-
magnetic field is produced by the coil windings. This
electromagnetic field draws the movable relay con-
tact point away from the fixed normally closed con-
tact point, and holds it against the fixed normally
open contact point. When the relay coil is de-ener-
gized, 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 headlamp low beam relay terminals are con-
nected to the vehicle electrical system through a con-
nector receptacle in the Junction Block (JB). The
inputs and outputs of the headlamp low beam relay
include:
²Common Feed Terminal- The common feed
terminal (30) receives battery current at all times
from a fuse in the Power Distribution Center (PDC)
through a fused B(+) circuit.
²Coil Ground Terminal- The coil ground termi-
nal (85) receives battery current at all times from a
fuse in the PDC through a fused B(+) circuit.
Fig. 37 ISO Micro Relay
30 - COMMON FEED
85 - COIL GROUND
86 - COIL BATTERY
87 - NORMALLY OPEN
87A - NORMALLY CLOSED
KJLAMPS/LIGHTING - EXTERIOR 8L - 39
HEADLAMP LEVELING SWITCH (Continued)

²Coil Battery Terminal- The coil battery ter-
minal (86) is connected to a control output of the
Body Control Module (BCM) through a low beam
relay control circuit. The BCM controls headlamp low
beam operation by controlling a ground path through
this circuit.
²Normally Open Terminal- The normally open
terminal (87) is connected to the headlamp low beam
filaments through the low beam relay output circuit
and provides battery current to the headlamp low
beams whenever the relay is energized.
²Normally Closed Terminal- The normally
closed terminal (87A) is not connected in this appli-
cation.
The headlamp low beam relay can be diagnosed
using conventional diagnostic tools and methods.
DIAGNOSIS AND TESTING - HEADLAMP LOW
BEAM RELAY
The headlamp low beam relay (Fig. 38) is located
in the Junction Block (JB) under the driver side out-
board end of the instrument panel. 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.
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 headlamp low beam relay from the
JB. (Refer to 8 - ELECTRICAL/LAMPS/LIGHTING -
EXTERIOR/HEADLAMP LOW BEAM RELAY -
REMOVAL).
(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.(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.
Fig. 38 ISO Micro Relay
30 - COMMON FEED
85 - COIL GROUND
86 - COIL BATTERY
87 - NORMALLY OPEN
87A - NORMALLY CLOSED
8L - 40 LAMPS/LIGHTING - EXTERIORKJ
HEADLAMP LOW BEAM RELAY (Continued)