2003 JEEP GRAND CHEROKEE Body control module

INPUT SPEED SENSOR (4.7L) - BLACK 2 WAY
CAV CIRCUIT FUNCTION
1 T52 18RD/BK INPUT SPEED SENSOR SIGNAL
2 T13 18DB/BK SPEED SENSOR GROUND
INSTRUMENT CLUSTER - WHITE 12 WAY
CAV CIRCUIT FUNCTION
1 L61 20TN/LG LEFT TURN SIGNAL
2 L60 20TN RIGHT TURN SIGNAL
3- -
4- -
5 G9 20GY/BK RED BRAKE WARNING INDICATOR DRIVER
6 F33 20PK/RD FUSED B(+)
7 G5 20DB/WT FUSED IGNITION SWITCH OUTPUT (RUN-START)
8 D19 20VT/OR BODY CONTROL MODULE FLASH ENABLE
9 Z300 20BK GROUND
10 D25 20YL/VT/RD PCI BUS
11 Z132 20BK/OR GROUND
12 - -
INTAKE AIR TEMPERATURE SENSOR (DIESEL) - BLACK 2 WAY
CAV CIRCUIT FUNCTION
1 K4 20BK/LB SENSOR GROUND
2 K21 20DG/WT INTAKE AIR TEMPERATURE SENSOR SIGNAL
INTAKE AIR TEMPERATURE SENSOR (GAS) - GRAY 2 WAY
CAV CIRCUIT FUNCTION
1 K4 18BK/LB SENSOR GROUND
2 K21 18BK/RD INTAKE AIR TEMPERATURE SENSOR SIGNAL
WJ8W-80 CONNECTOR PIN-OUT 8W - 80 - 85

INTAKE PORT SWIRL ACTUATOR (DIESEL) - BLACK 3 WAY
CAV CIRCUIT FUNCTION
1 Z18 18BK GROUND
2 F15 18RD/DG FUSED AUTO SHUT DOWN RELAY OUTPUT
3 K900 18GY INTAKE PORT SWIRL ACTUATOR SIGNAL
INTRUSION TRANSCEIVER MODULE (BUILT-UP-EXPORT) - BLACK 6 WAY
CAV CIRCUIT FUNCTION
1 Z155 20BK GROUND
2- -
3 X75 20GY/LG SIREN SIGNAL CONTROL
4- -
5 D25 20YL/VT PCI BUS
6 F70 20PK FUSED B(+)
JUNCTION BLOCK BODY CONTROL MODULE - BLACK 26 WAY
CAV CIRCUIT FUNCTION
1 L308 PARK LAMP RELAY CONTROL
2 L26 FOG LAMP RELAY CONTROL
3 Q29 ACCESSORY DELAY RELAY CONTROL
4 L307 LOW BEAM RELAY CONTROL
5 G5 FUSED IGNITION SWITCH OUTPUT (RUN-START)
6 X4 HORN RELAY CONTROL
7 V16 WIPER HIGH/LOW RELAY CONTROL
8 G80 LIFTGATE FLIP-UP AJAR SWITCH SENSE
9 L11 HIGH BEAM RELAY CONTROL
10 L91 HAZARD SWITCH SENSE
11 C80 REAR WINDOW DEFOGGER RELAY CONTROL
12 Z2 GROUND
13 L96 (BUILT-UP-EXPORT) REAR FOG LAMP RELAY CONTROL
14 L7 PARK LAMP RELAY OUTPUT
15 Z1 GROUND
16 M2 COURTESY LAMP DRIVER
17 - -
18 - -
19 M20 COURTESY LAMP LOAD SHED
20 V55 WIPER PARK SWITCH SENSE
21 G78 LIFTGATE AJAR SWITCH SENSE
22 G10 SEAT BELT SWITCH SENSE
23 G77 LEFT REAR DOOR AJAR SWITCH SENSE
24 G73 LIFTGATE COURTESY DISABLE
25 V23 FUSED IGNITION SWITCH OUTPUT (RUN-ACC)
26 M1 FUSED B(+)
8W - 80 - 86 8W-80 CONNECTOR PIN-OUTWJ

CONNECTOR NAME/
NUMBERCOLOR LOCATION FIG.
Blower Motor Controller (AZC) BK Behind Right Hand Side of
Instrument PanelN/S
Blower Motor Resistor Block
(MTC)BK Behind Right Hand Side of
Instrument PanelN/S
Body Control Module - C1 GY Lower Left Side of Instrument Panel 21, 22
Body Control Module-C2 -LHD WT Lower Left Side of Instrument Panel 21
Body Control Module-C2 -
RHDGY Lower Left Side of Instrument Panel 22
Boost Pressure Sensor
(Diesel)BK Top Front of Engine N/S
Brake Lamp Switch GY Brake Pedal Arm 31
C100 BK Right Front Engine Compartment 2, 5
C101 (4.0L RHD) LTGY Rear of Engine Compartment 15
C101 (4.7L RHD) BK Rear of Engine Compartment N/S
C102 (Diesel) BK Left Rear Engine Compartment 4, 7
C102 (Gas) BK Right Rear Engine Compartment 5, 10, 11, 14, 15, 18
C103 (Diesel) LTGY Rear of Engine 4, 7
C103 (Gas) GY Right Rear Engine Compartment 5, 10 11, 14, 15
C104 LTGY Right Rear Engine Compartment 14 18
C105 (Diesel) GY Right Rear Engine Compartment 4, 7, 8
C106 (Diesel) GY Lower Right Instrument Panel N/S
C106 (Gas RHD) GY Lower Right Instrument Panel N/S
C107 (Diesel) GY Left Rear Engine Compartment 4
C107 (LHD) BK Passenger Side Near Kick Panel 3, 30, 35
C107 (RHD) GY Passenger Side Near Kick Panel 3, 31
C108 BK Left Cowl 3, 4
C109 BK Near Transfer Case switch 12
C110 (Diesel) GY Top of Engine Near Glow Plugs 4, 7
C111 BK Left Front Frame Near Windshield
Washer Pump1, 3, 4
C112 BK Right Front Frame Near Horns 1, 5
C113 (Diesel) LTGY Rear of Engine 7, 8
C200 - LHD GY Passenger Side Near Kick Panel 19, 21, 35
C200 - RHD BK Passenger Side Near Kick Panel 20, 22
C201) WT Below Center Floor Console, Near
Park Brake19, 20, 21, 22
C202 WT HVAC Unit, Right Side of Instrument
Panel19, 20, 21, 22
C203 (AZC) WT HVAC Unit, Right Side of Instrument
Panel19, 20, 21, 22
C300 (LHD) GY Near Junction Block 30, 33
C301 (RHD) BK Near Junction Block 31
C302 BK At Driver Door 24, 25, 30, 31
8W - 91 - 2 8W-91 CONNECTOR/GROUND/SPLICE LOCATIONWJ
CONNECTOR/GROUND/SPLICE LOCATION (Continued)

CONNECTOR NAME/
NUMBERCOLOR LOCATION FIG.
Fuel Pump Module (Gas) BK Near Fuel Tank 33, 35
Fuel Tank Module Diesel) BK Near Fuel Tank 33, 35
Generator (Diesel) LTGY At Generator 8
Generator (Gas) BK At Generator N/S
Glove Box Lamp BK Inside Glove Box 19, 20, 22
Headlamp Leveling Switch
(Built-Up-Export)WT Driver Side of Instrument Panel 20
Hood Ajar Switch BK Left Side of Engine Compartment 3, 4
Horn No.1 BK Right Front Fascia 5
Horn No.2 BK Right Front Fascia 5
Hydraulic Cooling Module BK Right Front of Engine Compartment 5
Idle Air Control Motor BK Left Side of Engine Near Throttle
Body13
Ignition Switch - C1 WT On Steering Column 23
Ignition Switch - C2 BK On Steering Column 23
Input Speed Sensor (4.7L) BK Left Side of Transmission 16
Instrument Cluster WT At Instrument Cluster 19, 20
Intake Air Temperature Sensor
(Gas)GY Left Side of Engine 9, 13
Intake Air Temperature Sensor
(Diesel)BK Near T/O for Crankcase Heater 8
Intake Port Swirl Actuator
(Diesel)BK Right Rear of Engine Compartment N/S
Intrusion Transceiver Module
(Built-up-Export)BK In The Overhead N/S
Junction Block - C1 BK At Junction Block 30, 31, 33
Junction Block - C2 BK At Junction Block 30, 31
Junction Block - C3 BK At Junction Block 21, 22, 30
Junction Block - C4 WT At Junction Block 30, 31
Junction Block - C5 WT At Junction Block 30, 31
Knock Sensor (4.7L High
Output)BK Right Rear Side of Engine, Near
Coil on Plug No.8N/S
Leak Detection Pump (Except
Built-Up-Export)Left Front Wheel Opening 3
Left Courtesy Lamp BK Left Side of Instrument Panel 21 22, 23
Left Curtain Airbag BK Near Left C Pillar 37
Left Door Handle Courtesy
LampBK At Lamp N/S
Left Fog Lamp BK At Lamp 3, 4
Left Front Door Speaker WT In Left Front Door 24, 27
Left Front Impact Sensor BK Left Front Frame Near Windshield
Washer Pump3, 4
Left Front Park Lamp WT At Lamp N/S
8W - 91 - 6 8W-91 CONNECTOR/GROUND/SPLICE LOCATIONWJ
CONNECTOR/GROUND/SPLICE LOCATION (Continued)

JUNCTION BLOCK
DESCRIPTION
An electrical Junction Block (JB) is concealed
beneath the driver side of the instrument panel in
the passenger compartment of the vehicle (Fig. 3).
The JB combines the functions previously provided
by a separate fuseblock module and relay center. The
JB serves to simplify and centralize numerous elec-
trical components, as well as to distribute electrical
current to many of the accessory systems in the vehi-
cle. It also eliminates the need for numerous splice
connections. The JB houses up to thirty-three blade-
type mini fuses, up to two blade-type automatic
resetting circuit breakers, the electronic combination
flasher, the Daytime Running Lamp (DRL) module
(Canada only) and up to twelve International Stan-
dards Organization (ISO) relays (three standard-type
and nine micro-type). The JB also incorporates an
integral connector and mounting for the Body Con-
trol Module (BCM). The BCM is secured with four
screws directly to the dash panel side of the JB.
Refer toBody Control Modulein Electronic Con-
trol Modules for additional information covering the
BCM.
The molded plastic JB housing has integral mounts
that are secured with two screws and two snap
retainers to the instrument panel steering column
support bracket behind the instrument panel steer-ing column opening cover. The JB is concealed above
the molded plastic instrument panel fuse cover. Inte-
gral latches molded into the fuse cover secure it the
JB, the BCM and the 16-way data link connector tab
of the instrument panel steering column support
bracket. The fuse cover can be pulled downward to
disengage the latches and provide service access to
all of the fuses, relays and wire harness connectors of
the JB. The fuse cover has a fuse puller and spare
fuses secured to its upper surface. Refer toInstru-
ment Panel Fuse Coverin Body for additional ser-
vice information.
The JB unit cannot be repaired and is only ser-
viced as an assembly. If any internal circuit or the JB
housing is faulty or damaged, the entire JB unit
must be replaced. The BCM is available for separate
service replacement.
OPERATION
All of the circuits entering and leaving the Junc-
tion Block (JB) do so through up to five wire harness
connectors, which are connected to the JB through
integral connector receptacles molded into the JB
housing. Internal connection of all of the JB circuits
is accomplished by a printed circuit board. There are
also two separate wire harness connections to con-
nector receptacles that are integral to the BCM.
Refer toJunction Blockin Wiring Diagrams for
additional information and the location of complete
JB circuit diagrams.
REMOVAL
WARNING: DISABLE THE AIRBAG SYSTEM
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, OR INSTRUMENT PANEL
COMPONENT DIAGNOSIS OR SERVICE. DISCON-
NECT AND ISOLATE THE BATTERY NEGATIVE
(GROUND) CABLE, THEN WAIT TWO MINUTES FOR
THE AIRBAG SYSTEM CAPACITOR TO DISCHARGE
BEFORE PERFORMING FURTHER DIAGNOSIS OR
SERVICE. THIS IS THE ONLY SURE WAY TO DIS-
ABLE THE AIRBAG SYSTEM. FAILURE TO TAKE
THE PROPER PRECAUTIONS COULD RESULT IN
ACCIDENTAL AIRBAG DEPLOYMENT AND POSSI-
BLE PERSONAL INJURY.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the fuse cover from the bottom of the
Junction Block (JB).
(3) Remove the steering column opening cover
from the instrument panel. Refer toSteering Col-
umn Opening Coverin Body for the location of
steering column opening cover removal procedures.
Fig. 3 Junction Block Location
1 - REAR LATCHES
2 - JUNCTION BLOCK AND BODY CONTROL MODULE UNIT
3 - INSTRUMENT PANEL FUSE COVER
4 - SIDE LATCH
5 - FRONT LATCHES
WJ8W-97 POWER DISTRIBUTION 8W - 97 - 5

(4) Reach behind the JB to disconnect the two
instrument panel wire harness connectors from the
Body Control Module (BCM) connector receptacles
located near the bottom of the JB (Fig. 4).
(5) Reach behind the JB to remove the screw that
secures the instrument panel wire harness bulkhead
connector to the connector receptacle located near the
top of the JB and disconnect the connector.
(6) Disconnect the fused B(+) and the IOD wire
harness connectors from the connector receptacles
located near the bottom of the JB (Fig. 5).
(7) Remove the screws that secure the right and
left body wire harness bulkhead connectors to the
connector receptacles located near the center of the
JB and disconnect the connectors.
(8) Remove the two screws that secure the JB to
the instrument panel steering column support
bracket (Fig. 6).
(9) To disengage the two snap clips that secure the
top of the JB to the instrument panel steering col-
umn support bracket, grasp the bottom of the junc-
tion block firmly with both hands and pull it
downward sharply.
(10) Remove the JB from the instrument panel
steering column support bracket.
INSTALLATION
NOTE: If the Junction Block (JB) is being replaced
with a new unit, be certain to transfer each of the
optional fuses, circuit breakers and relays from thefaulty JB to the proper cavities of the replacement
JB. Refer to Junction Block in Wiring Diagrams for
the location of complete circuit diagrams and cavity
assignments for the JB. The Body Control Module
(BCM) must also be transferred to the new JB.
Refer to Body Control Module in Electronic Control
Modules for the location of the BCM removal and
installation procedures.
(1)
Position the JB into its mounting location on the
instrument panel steering column support bracket.
(2) Align the snap clips at the top of the JB with
the mounting holes in the instrument panel steering
column support bracket.
(3) Grasp the bottom of the JB firmly with both
hands and push it upward sharply to engage the two
snap clips that secure the top of the JB to the instru-
ment panel steering column support bracket.
(4)
Install and tighten the two screws that secure the
JB to the instrument panel steering column support
bracket. Tighten the screws to 2.2 N´m (20 in. lbs.).
Fig. 4 Junction Block Connections
1 - SCREW
2 - JUNCTION BLOCK
3 - BULKHEAD CONNECTOR
4 - BODY CONTROL MODULE
5 - INSTRUMENT PANEL WIRE HARNESS CONNECTORS
Fig. 5 Junction Block Connections
1 - SNAP CLIPS
2 - SCREW
3 - CONNECTOR
4 - LEFT BODY WIRE HARNESS
5 - IOD CONNECTOR
6 - FUSED B+ CONNECTOR
7 - RIGHT BODY WIRE HARNESS
8 - SCREW
9 - CONNECTOR
10 - JUNCTION BLOCK
8W - 97 - 6 8W-97 POWER DISTRIBUTIONWJ
JUNCTION BLOCK (Continued)

ground at all times. If not OK, repair the open
ground circuit to ground as required.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the steering column opening cover
from the instrument panel. Refer toSteering Col-
umn Opening Coverin Body for the procedure.
(3) The power outlet / cigar lighter relay is located
on the left side of the combination flasher in the
junction block.
(4) Remove the power outlet / cigar lighter relay
from the junction block.
INSTALLATION
(1) Position the power outlet / cigar lighter relay in
the proper receptacle in the junction block.
(2) Align the power outlet / cigar lighter relay ter-
minals with the terminal cavities in the junction
block receptacle.
(3) Push in firmly on the power outlet / cigar
lighter relay until the terminals are fully seated in
the terminal cavities in the junction block receptacle.
(4) Install the steering column opening cover onto
the instrument panel. Refer toSteering Column
Opening Coverin Body for the procedure.
(5) Reconnect the battery negative cable.
IOD WIRE HARNESS
CONNECTOR
DESCRIPTION
All vehicles are equipped with an Ignition-Off
Draw (IOD) connector that is located in a molded
connector receptacle on the lower rear surface of the
Junction Block (JB) housing (Fig. 17). The JB is con-
cealed above the molded plastic instrument panel
fuse cover. Integral latches molded into the fuse
cover secure it the JB, the Body Control Module
(BCM) and the 16-way data link connector tab of the
instrument panel steering column support bracket.
The fuse cover can be pulled downward to disengage
the latches and provide service access to all of the
fuses, relays and wire harness connectors of the JB.
Refer toInstrument Panel Fuse Coverin the
index of this service manual for the location of addi-
tional service information covering the fuse cover.
OPERATION
The term ignition-off draw identifies a normal con-
dition where power is being drained from the battery
with the ignition switch in the Off position. The IOD
connector feeds the memory and sleep mode func-
tions for some of the electronic modules in the vehicleas well as various other accessories that require bat-
tery current when the ignition switch is in the Off
position, including the clock.
The IOD connector can be used by the vehicle
owner as a convenient means of reducing battery
depletion when a vehicle is to be stored for periods
not to exceed about twenty days (short-term storage).
Simply disconnect the IOD connector from the JB
receptacle. However, it must be remembered that dis-
connecting the IOD connector will not eliminate IOD,
but only reduce this normal condition. When a vehi-
cle will not be used for more than twenty days, but
less than thirty days, remove the IOD fuse from the
Power Distribution Center (PDC). If a vehicle will be
stored for more than about thirty days, the battery
negative cable should be disconnected to eliminate
normal IOD; and, the battery should be tested and
recharged at regular intervals during the vehicle
storage period to prevent the battery from becoming
discharged or damaged. Refer toIgnition-Off Draw
Fig. 17 Ignition-Off Draw Connector
1 - SNAP CLIPS
2 - SCREW
3 - CONNECTOR
4 - LEFT BODY WIRE HARNESS
5 - IOD CONNECTOR
6 - FUSED B+ CONNECTOR
7 - RIGHT BODY WIRE HARNESS
8 - SCREW
9 - CONNECTOR
10 - JUNCTION BLOCK
WJ8W-97 POWER DISTRIBUTION 8W - 97 - 15
POWER OUTLET RELAY (Continued)

FuseandBatteryin the index in this service man-
ual for the location of additional service information
covering the ignition-off draw fuse and the battery.
FUSE COVER
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Pull down on the rear edge (nearest the rear of
the vehicle) of the instrument panel fuse cover until
the rear latches unsnap from the tabs on the lower
junction block housing and the side latch unsnaps
from the tab on the instrument panel steering col-
umn support bracket outboard of the 16-way data
link connector (Fig. 18).
(3) Move the instrument panel fuse cover towards
the front of the vehicle to disengage the front latches
from the mounting slots in the lower housing of the
body control module.
(4) Remove the fuse cover from under the instru-
ment panel.
INSTALLATION
(1) Position the two front latches of the instrument
panel fuse cover within the two locator channel for-
mations on the bottom of the body control module
housing (Fig. 19).
(2) While applying a slight upward pressure to the
instrument panel fuse cover over the front latches,
slowly slide the front latches through the locator
channels toward the front of the vehicle until thelatches exit the front of the locator channels. This
will locate the front latches at the mounting slots in
the lower housing of the body control module.
(3) Apply a slight rearward pressure on the instru-
ment panel fuse cover to engage the front latches in
the mounting slots in the lower housing of the body
control module.
(4) Swing the rear edge (nearest the rear of the
vehicle) of the instrument panel fuse cover up toward
the junction block.
(5) Press firmly upward on the instrument panel
fuse cover over the rear latches until the latches
snap into place over the tabs on the lower edge of the
junction block housing.
(6) Press firmly upward on the 16-way data link
connector cover formation of the instrument panel
fuse cover until the side latch snaps into place over
the tab on the outboard side of the instrument panel
steering column support bracket.
(7) Reconnect the battery negative cable.
REAR POWER OUTLET
DESCRIPTION - REAR POWER OUTLET
A rear accessory power outlet is optional equip-
ment on this model. The rear power outlet is
installed in the lower right quarter trim panel near
the right liftgate opening pillar in the cargo area of
Fig. 18 Instrument Panel Fuse Cover Remove/Install
1 - REAR LATCHES
2 - JUNCTION BLOCK AND BODY CONTROL MODULE UNIT
3 - INSTRUMENT PANEL FUSE COVER
4 - SIDE LATCH
5 - FRONT LATCHES
Fig. 19 Instrument Panel Fuse Cover Locator
Channels
1 - JUNCTION BLOCK
2 - SCREWS (4)
3 - BODY CONTROL MODULE
4 - FUSE COVER LOCATOR CHANNELS
5 - FUSE COVER MOUNTING SLOTS
6 - INSTRUMENT PANEL WIRE HARNESS CONNECTORS
8W - 97 - 16 8W-97 POWER DISTRIBUTIONWJ
IOD WIRE HARNESS CONNECTOR (Continued)