2002 JEEP LIBERTY Power distribution unit

(3) Position the multi-function switch onto the
steering column lock housing. Be certain that the
switch alignment posts and locator tabs are fully
seated on the lock housing.
(4) Position the upper and lower shrouds onto the
steering column.
(5) Align the snap features on the lower shroud
with the receptacles on the upper shroud and apply
hand pressure to snap them together.
(6) From below the steering column, install and
tighten the two screws that secure the lower shroud
to the upper shroud. Tighten the screws to 2 N´m (20
in. lbs.).
(7) If the vehicle is equipped with the optional tilt
steering column, move the tilt steering column back
to the fully raised position and move the tilt release
lever into the locked (up) position.
(8) Reconnect the battery negative cable.
PARK LAMP RELAY
DESCRIPTION
The park lamp relay is located in the Junction
Block (JB) below the driver side outboard end of the
instrument panel in the passenger compartment of
the vehicle. The park lamp relay is a conventional
International Standards Organization (ISO) micro
relay (Fig. 53). 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 therequired inputs and outputs by five integral male
spade-type terminals that extend from the bottom of
the relay base.
The park lamp relay cannot be adjusted or
repaired and, if faulty or damaged, the unit must be
replaced.
OPERATION
The park lamp relay is an electromechanical
switch that uses a low current input from the Body
Control Module (BCM) to control a high current out-
put to the park 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 park lamp relay terminals are connected to
the vehicle electrical system through a connector
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) is connected to the park lamps through
the park lamp relay output circuit and provides
ground to the park lamps when the relay is de-ener-
gized, and battery current to the park lamps when-
ever the relay is energized.
²Coil Ground Terminal- The coil ground termi-
nal (85) is connected to a control output of the Body
Control Module (BCM) through a park lamp relay
control circuit. The BCM controls park lamp opera-
tion by controlling a ground path through this cir-
cuit.
²Coil Battery Terminal- The coil battery ter-
minal (86) receives battery current at all times from
a fuse in the PDC through a fused B(+) circuit.
²Normally Open Terminal- The normally open
terminal (87) receives battery current at all times
from a fuse in the Power Distribution Center (PDC)
through a fused B(+) circuit.
²Normally Closed Terminal- The normally
closed terminal (87A) is connected to ground at all
times through a ground circuit that receives 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
Fig. 53 ISO Micro Relay
30 - COMMON FEED
85 - COIL GROUND
86 - COIL BATTERY
87 - NORMALLY OPEN
87A - NORMALLY CLOSED
8L - 54 LAMPS/LIGHTING - EXTERIORKJ
MULTI-FUNCTION SWITCH (Continued)

FRONT FOG LAMPS
Vehicles equipped with optional front fog lamps
have a premium Body Control Module (BCM), a front
fog lamp relay installed in the Junction Block (JB),
and a front fog lamp switch integral to the left (light-
ing) control stalk of the multi-function switch. The
front fog lamps have a path to ground at all times
through their connection to the front fascia wire har-
ness from two take outs of the headlamp and dash
wire harness with eyelet terminal connectors that
are secured by ground screws to the left inner fender
shield in the engine compartment. The BCM controls
front fog lamp operation by monitoring the exterior
lighting switch input from the multi-function switch,
then energizing or de-energizing the front fog lamp
relay control coil; and, by sending the appropriate
electronic message to the instrument cluster over the
Programmable Communications Interface (PCI) data
bus to turn the front fog lamp indicator on or off.
When the front fog lamp relay is energized, it pro-
vides battery current from a fused B(+) fuse in the
JB to the front fog lamps through the front fog lamp
relay output circuit. The BCM provides a battery
saver (load shedding) feature for the front fog lamps,
which will turn these lamps off if they are left on for
more than about eight minutes with the ignition
switch in the Off position. In certain markets where
required, the front fog lamps are also turned off by
the BCM whenever the headlamp high beams are
selected. Each front fog lamp includes an integral
adjustment screw to be used for static aiming the fog
lamp beams.
HAZARD WARNING LAMPS
With the hazard switch in the On position, the
hazard warning system is activated causing the haz-
ard switch button illumination lamp, the right and
left turn signal indicators, and the right and left turn
signal lamps to flash on and off. When the hazard
warning system is activated, the circuitry within the
hazard switch and electronic combination flasher
unit will repeatedly energize and de-energize two
internal relays that switch battery current from a
fused B(+) fuse in the Junction Block (JB) to the
right side and left side turn signal indicators, and
turn signal lamps through the right and left turn sig-
nal circuits. The flashing of the hazard switch button
illumination lamp is performed internally by the haz-
ard switch and combination flasher unit circuit
board. The hazard warning lamps can also be ener-
gized by the Body Control Module (BCM) through a
hazard lamp control circuit input to the hazard
switch and combination flasher unit.HEADLAMPS
The headlamp system includes the Body Control
Module (BCM), a low beam relay installed in the
Junction Block (JB), a high beam relay installed in
the JB (except Canada), a solid state Daytime Run-
ning Lamps (DRL) relay installed in the JB (Canada
only), and the exterior lighting (headlamp and dim-
mer) switches integral to the left (lighting) control
stalk of the multi-function switch. The headlamp
bulbs have a path to ground at all times through
their connection to the grille opening reinforcement
wire harness from two take outs of the headlamp and
dash wire harness with eyelet terminal connectors
that are secured by ground screws to the left inner
fender shield in the engine compartment. The BCM
controls the headlamp operation by monitoring the
exterior lighting switch inputs from the multi-func-
tion switch, then energizing or de-energizing the con-
trol coils of the low beam relay, the high beam relay,
or the solid state circuitry of the DRL relay; and, by
sending the appropriate electronic message to the
instrument cluster over the Programmable Commu-
nications Interface (PCI) data bus to turn the high
beam indicator on or off. When each respective relay
is energized, it provides battery current from a fused
B(+) fuse in the Power Distribution Center (PDC)
through a relay (low beam, high beam, or DRL) out-
put circuit and four separate fuses in the JB through
individual fused right and left, low and high beam
output circuits to the appropriate headlamp bulb fil-
aments. The BCM provides a battery saver (load
shedding) feature for the headlamps, which will turn
these lamps off if they are left on for more than
about eight minutes with the ignition switch in the
Off position; and, a headlamp delay feature with a
DRBIIItscan tool programmable delay interval.
Each headlamp includes an integral adjustment
screw to be used for static aiming of the headlamp
beams.
HEADLAMP LEVELING
In certain markets where required, a headlamp
leveling system is provided on the vehicle. The head-
lamp leveling system includes unique headlamp units
equipped with a headlamp leveling actuator motor,
and a rotary thumbwheel actuated headlamp leveling
switch on the instrument panel. The headlamp level-
ing system allows the headlamp beams to be
adjusted to one of four vertical positions to compen-
sate for changes in inclination caused by the loading
of the vehicle suspension. The actuator motors are
mechanically connected through an integral pushrod
to an adjustable headlamp reflector. The headlamp
leveling switch is a resistor multiplexed unit that
provides one of four voltage outputs to the headlamp
leveling motors. The headlamp leveling motors will
8Ls - 6 LAMPSKJ
LAMPS/LIGHTING - EXTERIOR (Continued)

move the headlamps to the selected position based
upon the voltage input received from the switch. The
headlamp leveling motors and switch have a path to
ground at all times. The headlamp leveling compo-
nents operate on battery current received through
the fused park lamp relay output circuit so that the
system will only operate when the exterior lighting is
turned on.
PARK LAMPS
The park lamps system includes the Body Control
Module (BCM), a park lamp relay installed in the
Junction Block (JB), and the exterior lighting switch
integral to the left (lighting) control stalk of the
multi-function switch. The front park lamp and side
marker or, if equipped, the front position lamp bulbs
each have a path to ground at all times through their
connections to the grille opening reinforcement wire
harness from two take outs of the headlamp and
dash wire harness with eyelet terminal connectors
that are secured by ground screws to the left inner
fender shield in the engine compartment. The rear
park lamp bulbs and license plate lamp have a path
to ground at all times through their connection to the
rear lighting wire harness from a take out of the rear
body wire harness with an eyelet terminal connector
that is secured by a ground screw to the base of the
right D-pillar behind the quarter trim panel. The
BCM controls the park lamp operation by monitoring
the exterior lighting switch inputs from the multi-
function switch, then energizing or de-energizing the
control coil of the park lamp relay. When the park
lamp relay is energized, it provides battery current
from a fused B(+) fuse in the Power Distribution
Center (PDC) through a park lamp relay output cir-
cuit and a separate fuse in the JB through a fused
park lamp relay output circuit to the appropriate
lamp bulb filaments. The BCM provides a battery
saver (load shedding) feature for the park lamps,
which will turn these lamps off if they are left on for
more than about eight minutes with the ignition
switch in the Off position.
REAR FOG LAMPS
Rear fog lamps are installed on vehicles manufac-
tured for certain markets where they are required.
The rear fog lamp system includes a premium Body
Control Module (BCM), a rear fog lamp relay
installed in the Junction Block (JB), and a rear fog
lamp switch integral to the left (lighting) control
stalk of the multi-function switch. The rear fog lamps
have a path to ground at all times through their con-
nection to the rear lighting wire harness from a take
out of the rear body wire harness with an eyelet ter-
minal connector that is secured by a ground screw to
the base of the right D-pillar behind the quarter trimpanel. The BCM controls rear fog lamp operation by
monitoring the exterior lighting switch input from
the multi-function switch, then energizing or de-ener-
gizing the rear fog lamp relay control coil; and, by
sending the appropriate electronic message to the
instrument cluster over the Programmable Commu-
nications Interface (PCI) data bus to turn the rear
fog lamp indicator on or off. When the rear fog lamp
relay is energized, it provides battery current from a
fused B(+) fuse in the JB to the rear fog lamps
through the rear fog lamp relay output circuit. The
BCM provides a battery saver (load shedding) feature
for the rear fog lamps, which will turn these lamps
off if they are left on for more than about eight min-
utes with the ignition switch in the Off position.
TURN SIGNAL LAMPS
When the left control stalk of the multi-function
switch is moved up (right turn) or down (left turn),
the turn signal system is activated causing the
selected right or left turn signal indicator, and right
or left turn signal lamps to flash on and off. When
the turn signal system is activated, the circuitry
within the turn signal switch and the hazard switch/
electronic combination flasher unit will repeatedly
energize and de-energize one of two internal relays
that switch battery current from a fused ignition
switch output (run) fuse in the Junction Block (JB) to
the right side or left side turn signal indicators and
turn signal lamps through the right or left turn sig-
nal circuits. The ElectroMechanical Instrument Clus-
ter (EMIC) chime tone generator will generate an
audible turn signal cancel warning each time the
vehicle is driven for a distance of about 3.2 kilome-
ters (about two miles) with a turn signal indicator
flashing. The EMIC uses Programmable Communica-
tions Interface (PCI) data bus distance messages
from the Powertrain Control Module (PCM) and a
hard wired input from the turn signal switch cir-
cuitry of the multi-function switch to determine when
to sound the turn signal cancel warning.
DIAGNOSIS AND TESTING - LAMPS/LIGHTING
- EXTERIOR
The hard wired circuits and components of the
exterior lighting systems may be diagnosed and
tested using conventional diagnostic tools and proce-
dures. However, conventional diagnostic methods
may not prove conclusive in the diagnosis of the Body
Control Module (BCM), the ElectroMechanical
Instrument Cluster (EMIC), the Powertrain Control
Module (PCM), or the Programmable Communica-
tions Interface (PCI) data bus network. The most
reliable, efficient, and accurate means to diagnose
the BCM, the EMIC, the PCM, and the PCI data bus
network inputs and outputs related to the various
KJLAMPS8Ls-7
LAMPS/LIGHTING - EXTERIOR (Continued)

system. Constant battery voltage is supplied to the
flasher so that it can perform the hazard warning func-
tion, and ignition switched battery voltage is supplied
for the turn signal function. The Integrated Circuit (IC)
within the combination 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 sig-
nals, and from the hazard switch contacts or the BCM
for the hazard warning signals. A special design feature
of the combination flasher allows it to9sense9that a
turn signal circuit 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 flashes-per-minute or higher). Conventional flash-
ers 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 featuresa 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)
8Ls - 20 LAMPSKJ
COMBINATION FLASHER (Continued)

(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) is connected to a control output of the Body
Control Module (BCM) through a head lamp relay
control circuit. The BCM controls head lamp opera-
tion by controlling a ground path through this 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.
²Normally Open Terminal- The normally open
terminal (87) is connected to the headlamp high
beam filaments through the high beam relay output
circuit and provides battery current to the headlamp
high beams whenever the relay is energized.
Fig. 28 ISO Micro Relay
30 - COMMON FEED
85 - COIL GROUND
86 - COIL BATTERY
87 - NORMALLY OPEN
87A - NORMALLY CLOSED
KJLAMPS8Ls-33
HEADLAMP BULB (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
KJLAMPS8Ls-39
HEADLAMP LEVELING SWITCH (Continued)

(3) Position the multi-function switch onto the
steering column lock housing. Be certain that the
switch alignment posts and locator tabs are fully
seated on the lock housing.
(4) Position the upper and lower shrouds onto the
steering column.
(5) Align the snap features on the lower shroud
with the receptacles on the upper shroud and apply
hand pressure to snap them together.
(6) From below the steering column, install and
tighten the two screws that secure the lower shroud
to the upper shroud. Tighten the screws to 2 N´m (20
in. lbs.).
(7) If the vehicle is equipped with the optional tilt
steering column, move the tilt steering column back
to the fully raised position and move the tilt release
lever into the locked (up) position.
(8) Reconnect the battery negative cable.
PARK LAMP RELAY
DESCRIPTION
The park lamp relay is located in the Junction
Block (JB) below the driver side outboard end of the
instrument panel in the passenger compartment of
the vehicle. The park lamp relay is a conventional
International Standards Organization (ISO) micro
relay (Fig. 53). 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 therequired inputs and outputs by five integral male
spade-type terminals that extend from the bottom of
the relay base.
The park lamp relay cannot be adjusted or
repaired and, if faulty or damaged, the unit must be
replaced.
OPERATION
The park lamp relay is an electromechanical
switch that uses a low current input from the Body
Control Module (BCM) to control a high current out-
put to the park 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 park lamp relay terminals are connected to
the vehicle electrical system through a connector
receptacle in the Junction Block (JB). The inputs and
outputs of the park lamp relay include:
²Common Feed Terminal- The common feed
terminal (30) is connected to the park lamps through
the park lamp relay output circuit and provides
ground to the park lamps when the relay is de-ener-
gized, and battery current to the park lamps when-
ever the relay is energized.
²Coil Ground Terminal-
The coil ground termi-
nal (85) is connected to a control output of the Body
Control Module (BCM) through a park lamp relay con-
trol circuit. The BCM controls park lamp operation by
controlling a ground path through this circuit.
²Coil Battery Terminal- The coil battery ter-
minal (86) receives battery current at all times from
a fuse in the PDC through a fused B(+) circuit.
²Normally Open Terminal- The normally open
terminal (87) receives battery current at all times
from a fuse in the Power Distribution Center (PDC)
through a fused B(+) circuit.
²Normally Closed Terminal- The normally
closed terminal (87A) is connected to ground at all
times through a ground circuit that receives 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
Junction Block (JB).
Fig. 53 ISO Micro Relay
30 - COMMON FEED
85 - COIL GROUND
86 - COIL BATTERY
87 - NORMALLY OPEN
87A - NORMALLY CLOSED
8Ls - 54 LAMPSKJ
MULTI-FUNCTION SWITCH (Continued)

OPERATION
The power seat system receives battery current
through a fuse in the Power Distribution Center
(PDC) and a circuit breaker in the Junction Block,
regardless of the ignition switch position.
When a power seat switch control knob or knobs
are actuated, a battery feed and a ground path are
applied through the switch contacts to the appropri-
ate power seat track adjuster motor. The selected
adjuster motor operates to move the seat track
through its drive unit in the selected direction until
the switch is released, or until the travel limit of the
seat track is reached. When the switch is moved in
the opposite direction, the battery feed and ground
path to the motor are reversed through the switch
contacts. This causes the adjuster motor to run in the
opposite direction.
Refer to the owner's manual in the vehicle glove
box for more information on the features, use and
operation of the power seat system.
DIAGNOSIS AND TESTING - POWER SEATS
Before any testing of the power seat system is
attempted, the battery should be fully-charged and
all wire harness connections and pins cleaned and
tightened to ensure proper continuity and grounds.
Refer to the appropriate wiring information. The wir-
ing information includes wiring diagrams, proper
wire and connector repair procedures, further details
on wire harness routing and retention, as well as
pin-out and joint connector location views for the var-
ious wire harness connectors, splices and grounds.
(1) If all power seats are inoperative, check the
automatic resetting circuit breaker in the Junction
Block. (Refer to 8 - ELECTRICAL/POWER DISTRI-
BUTION/CIRCUIT BREAKER - DIAGNOSIS AND
TESTING).
(2) With the dome lamp on, apply the power seat
switch in the direction of the failure.
(3) If the dome lamp dims, the seat or the power
seat track may be jammed. Check under and behind
the seat for binding or obstructions.
(4) If the dome lamp does not dim, proceed with
testing of the individual power seat system compo-
nents and circuits.
SEAT TRACK
DESCRIPTION
The six-way power seat option includes a power
seat track assembly located under each front seat
(Fig. 2). The power seat track assembly replaces the
standard manually operated seat tracks. The lower
half of the power seat track is secured at the frontwith two bolts to the floor panel seat cross member,
and at the rear with one bolt and one nut to the floor
panel. Four bolts secure the bottom of the seat cush-
ion frame to the upper half of the power seat track
unit.
The power seat track assembly cannot be repaired,
and is serviced only as a complete assembly. If any
component in this assembly is faulty or damaged, the
entire power seat track must be replaced.
OPERATION
The power seat track unit includes three reversible
electric motors that are secured to the upper half of
the track unit. Each motor moves the seat adjuster
through a combination of worm-drive gearboxes and
screw-type drive units. Each of the three driver side
power seat track motors also has a position potenti-
ometer integral to the motor assembly, which elec-
tronically monitors the motor position.
The front and rear of the seat are operated by two
separate vertical adjustment motors. These motors
can be operated independently of each other, tilting
the entire seat assembly forward or rearward; or,
they can be operated in unison by selecting the
proper power seat switch functions, which will raise
or lower the entire seat assembly. The third motor is
the horizontal adjustment motor, which moves the
seat track in the forward and rearward directions.
Fig. 2 Power Seat Track - Typical
1 - POWER SEAT ADJUSTER AND MOTORS
2 - SEAT CUSHION FRAME
3 - POWER SEAT TRACK ASSEMBLY
KJPOWER SEATS 8N - 15
POWER SEATS (Continued)