2003 JEEP GRAND CHEROKEE fuse block

INSTALLATION - CHMSL
(1) Connect the wire harness connector.
(2) Position the CHMSL on liftgate.
(3) Install the screws attaching the CHMSL to the
liftgate.
COMBINATION FLASHER
DESCRIPTION
The combination flasher is located in the Junction
Block (JB) (Fig. 6). The JB is located underneath the
driver side of the instrument panel outboard of the
steering column. The combination flasher is a smart
relay that functions as both the turn signal system
and the hazard warning system flasher. The combi-
nation flasher contains active electronic Integrated
Circuitry (IC) elements. This flasher is designed to
handle the current flow requirements of the factory-
installed lighting. If supplemental lighting is added
to the turn signal lamp circuits, such as when towing
a trailer with lights, the combination flasher will
automatically try to compensate to keep the flash
rate the same.The combination flasher has nine blade-type termi-
nals that connect it to the vehicle electrical system.
Refer to the appropriate wiring information.
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 system and hazard warning system cir-
cuits.(Refer to 8 - ELECTRICAL/LAMPS/LIGHTING
- EXTERIOR - DIAGNOSIS AND TESTING - TURN
SIGNAL & HAZARD WARNING SYSTEM). The com-
bination flasher cannot be repaired or adjusted and,
if faulty or damaged, it must be replaced.
OPERATION
The combination flasher controls the following
inputs and outputs: B(+), fused ignition switch out-
put, left turn switch sense, right turn switch sense,
hazard switch sense, left front turn signal circuit,
right front turn signal circuit, left rear turn signal
circuit and right rear turn signal circuit. Constant
battery voltage is supplied to the flasher so that it
can perform the hazard warning function, and igni-
tion switched battery voltage is supplied for the turn
signal function. However, when the flasher is idle no
current is drawn through the module. The unit does
not become active until it is provided a signal ground
from the turn signal switch, hazard warning switch
or the Body Control Module (BCM).
The IC within the combination flasher (Fig. 7) con-
tains the logic that controls the flasher operation and
the flash rate. When a bulb is burnt out, or when a
circuit for a lamp is open, the turn signal flash rate
will increase. However, an open lamp circuit or burnt
out bulb does not change the hazard warning flash
rate.
Fig. 6 Combination Flasher
1 - COMBINATION FLASHER
2 - JUNCTION BLOCK
WJLAMPS/LIGHTING - EXTERIOR 8L - 7
CENTER HIGH MOUNTED STOP LAMP (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
FOG LAMPS DO NOT
ILLUMINATE1. Blown fuse for fog lamp. 1. Replace fuse. Refer to Electrical, Wiring
Information.
2. No Z1-ground at fog lamps. 2. Repair circuit ground. Refer to Electrical,
Wiring Information.
3. Faulty multifunction switch. 3. Refer to Electrical, Wiring Information.
4. Broken connector terminal or wire
splice in fog lamp circuit.4. Repair connector terminal or wire splice.
5. Defective or burned out bulb. 5. Replace bulb.
DAYTIME RUNNING LAMP
CONDITION POSSIBLE CAUSES CORRECTION
DAYTIME RUNNING LAMPS DO
NOT WORK1. Poor connection at DRL module. 1. Secure connector on DRL
module.
2. Parking brake engaged. 2. Disengage parking brake.
3. Parking brake circuit shorted to
ground.3. Check cluster telltale, refer to
Group 8W.
4. Headlamp circuit shorted to
ground.4. Refer to Group 8W.
5. Defective DRL relay. 5. Replace DRL relay.
6. Body controller not programed
with Canadian country code.6. Check country code.
7. DRL relay is missing. 7. Install DRL relay.
8. Blown fuse for DRL. 8. Replace fuse refer to Electrical,
Wiring Information.
Clicking or chattering when DRL is
on.1. Mechanical relay is installed in
the junction block.1. Ensure that the DRL relay is
installed in the proper socket in
junction block, and that no
mechanical relay exists in the low
beam socket.
DIAGNOSIS AND TESTING Ð HEADLAMP
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 other than
those indicated in the Bulb Application table. Dam-
age to lamp and/or Daytime Running Lamp Module
can result. Do not use fuses, circuit breakers or
relays having greater amperage value than indi-
cated on the fuse panel or in the Owners Manual.
Each vehicle is equipped with various lamp assem-
blies. A good power feed and ground are necessary forproper lighting operation. Grounding is provided by
the lamp socket when it comes in contact with the
metal body, or through a separate ground wire.
When changing lamp bulbs check the socket for
corrosion. If corrosion is present, clean it with a wire
brush and coat the inside of the socket lightly with
Mopar Multi-Purpose Grease or equivalent.
REMOVAL - BULB
(1) Remove the headlamp.
(2) Turn the bulb socket one quarter turn counter
clockwise.
(3) Remove the socket from lamp (Fig. 13).
(4) Remove the bulb from socket.
8L - 14 LAMPS/LIGHTING - EXTERIORWJ
HEADLAMP (Continued)

OPERATION
The EVIC has access to both non-switched and
ignition switched sources of battery current so that
some of its features remain operational at any time,
while others may only operate with the ignition
switch in the On position. When the ignition switch
is turned to the On position, the EVIC module VFD
will return to the last function being displayed before
the ignition was turned to the Off position.
The compass/temperature display is the normal
EVIC display. With the ignition switch in the On
position, momentarily depressing and releasing the
C/T (compass/temperature) push button switch will
cause the EVIC to return to the compass/tempera-
ture/trip computer display mode from any other
mode. While in the compass/temperature/trip com-
puter display mode, momentarily depressing and
releasing the Step push button will step through the
available trip computer display options.
The EVIC trip computer features several functions
that can be reset. The functions that can be reset
are: average fuel economy, trip odometer and elapsed
time. With the ignition switch in the On position and
with one of the functions of the trip computer that
can be reset currently displayed, depressing the
Reset push button twice within three seconds will
perform a global reset, and all of the trip computer
information that can be reset will be reset to zero.
With the ignition switch in the On position and the
function that is to be reset currently displayed,
momentarily depressing and releasing the Reset
push button once will perform a local reset, and only
the value of the displayed function will be reset to
zero. A global or local reset will only occur if the
function currently displayed is a function that can be
reset. The distance to service function can also be
reset using the local reset method, but it will reset
back to the Service Interval distance that is set in
the EVIC programmable features mode. Refer to
ELECTRONIC VEHICLE INFORMATION CEN-
TER PROGRAMMINGin the Service Procedures
section of this group for more information on setting
the Service Interval.
For more information on the features, control func-
tions and setting procedures for the EVIC module,
see the owner's manual in the vehicle glove box.
DIAGNOSIS AND TESTING - ELECTRONIC
VEHICLE INFORMATION CENTER
If the problem with the Electronic Vehicle Informa-
tion Center (EVIC) is a temperature reading of 130É
F or -40ÉF shown in the compass/temperature dis-
play, refer toAmbient Temperature Sensor Diag-
nosis and Testingin this group. If the problem with
the EVIC is an inaccurate or scrambled display, refer
toSelf-Diagnostic Testin this group. If the prob-lem with the EVIC is incorrect Vacuum Fluorescent
Display (VFD) dimming levels, use a DRBtscan tool
and the proper Diagnostic Procedures manual to test
for the correct dimming message inputs being
received from the Body Control Module (BCM) over
the Programmable Communications Interface (PCI)
data bus. If the problem is a no-display condition,
use the following procedures. For complete circuit
diagrams, refer toOverhead Consolein Wiring
Diagrams.
(1) Check the fused B(+) fuse in the junction block.
If OK, go to Step 2. If not OK, repair the shorted cir-
cuit or component as required and replace the faulty
fuse.
(2) Check for battery voltage at the fused B(+) fuse
in the junction block. If OK, go to Step 3. If not OK,
repair the open fused B(+) circuit to the fused B(+)
fuse in the PDC as required.
(3) Check the fused ignition switch output (run/
start) fuse in the junction block. If OK, go to Step 4.
If not OK, repair the shorted circuit or component as
required and replace the faulty fuse.
(4) Turn the ignition switch to the On position.
Check for battery voltage at the fused ignition switch
output (run/start) fuse in the junction block. If OK,
go to Step 5. If not OK, repair the open fused ignition
switch output (run/start) circuit to the ignition switch
as required.
(5) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Remove the overhead console. Check for continuity
between the ground circuit cavity of the roof wire
harness connector for the EVIC module and a good
ground. There should be continuity. If OK, go to Step
6. If not OK, repair the open ground circuit to ground
as required.
(6) Connect the battery negative cable. Check for
battery voltage at the fused B(+) circuit cavity of the
roof wire harness connector for the EVIC module. If
OK, go to Step 7. If not OK, repair the open fused
B(+) circuit to the fused B(+) fuse in the junction
block as required.
(7) Turn the ignition switch to the On position.
Check for battery voltage at the fused ignition switch
output (run/start) circuit cavity of the roof wire har-
ness connector for the EVIC module. If OK, refer to
Self-Diagnostic Testbelow for further diagnosis of
the EVIC module and the PCI data bus. If not OK,
repair the open fused ignition switch output (run/
start) circuit to the fuse in the junction block as
required.
SELF-DIAGNOSTIC TEST
A self-diagnostic test is used to determine that the
EVIC module is operating properly, and that all PCI
WJMESSAGE SYSTEMS 8M - 9
ELECTRONIC VEHICLE INFO CENTER (Continued)

This vehicle also offers several customer program-
mable features, which allows the selection of several
optional electronic features to suit individual prefer-
ences. (Refer to 8 - ELECTRICAL/OVERHEAD CON-
SOLE/ELECTRONIC VEHICLE INFO CENTER -
DESCRIPTION). Customer programmable feature
options affecting the power door lock system include:
²Auto Door Locks- Automatically locks all of
the vehicle doors and the liftgate when the vehicle
reaches a speed of about 24 kilometers-per-hour (15
miles-per-hour) with 10% throttle tip-in.
²Auto Unlock on Exit- Automatically unlocks
all of the vehicle doors and the liftgate when the
driver side front door is opened, if the vehicle is
stopped and the transmission gear selector is in the
Park or Neutral positions. This feature is linked to
the Auto Door Locks feature, and will only occur one
time following each Auto Door Lock event.
The power lock system for this vehicle can also be
operated remotely using the standard equipment
Remote Keyless Entry (RKE) system radio frequency
transmitters. (Refer to 8 - ELECTRICAL/POWER
LOCKS - DESCRIPTION - REMOTE KEYLESS
ENTRY SYSTEM).
The components of the power lock system include:
²Driver Door Module (DDM)
²Passenger Door Module (PDM)
²PCI Bus Messages
²Power Lock Motors
Certain functions and features of the power lock
system rely upon resources shared with other elec-
tronic modules in the vehicle over the Programmable
Communications Interface (PCI) data bus network.
The PCI data bus network allows the sharing of sen-
sor information. This helps to reduce wire harness
complexity, internal controller hardware, and compo-
nent sensor current loads. At the same time, this sys-
tem provides increased reliability, enhanced
diagnostics, and allows the addition of many new fea-
ture capabilities. For proper diagnosis of these elec-
tronic modules or of the PCI data bus network, the
use of a DRBIIItscan tool and the appropriate diag-
nostic information are required.
The other electronic modules that may affect power
lock system operation are as follows:
²Body Control Module (BCM)- (Refer to 8 -
ELECTRICAL/ELECTRONIC CONTROL MOD-
ULES/BODY CONTROL/CENTRAL TIMER MOD-
ULE - DESCRIPTION).
²Electronic Vehicle Information Center
(EVIC)- (Refer to 8 - ELECTRICAL/OVERHEAD
CONSOLE/ELECTRONIC VEHICLE INFO CENTER
- DESCRIPTION).
²Powertrain Control Module (PCM)- (Refer
to 8 - ELECTRICAL/ELECTRONIC CONTROLMODULES/POWERTRAIN CONTROL MODULE -
DESCRIPTION).
Hard wired circuitry connects the power lock sys-
tem components to the electrical system of the vehi-
cle. These hard wired circuits are integral to several
wire harnesses, which are routed throughout the
vehicle and retained by many different methods.
These circuits may be connected to each other, to the
vehicle electrical system and to the power lock sys-
tem components through the use of a combination of
soldered splices, splice block connectors, and many
different types of wire harness terminal connectors
and insulators. Refer to the appropriate wiring infor-
mation. The wiring information includes wiring dia-
grams, proper wire and connector repair procedures,
further details on wire harness routing and reten-
tion, as well as pin-out and location views for the
various wire harness connectors, splices and grounds.
DESCRIPTION - REMOTE KEYLESS ENTRY
SYSTEM
A Radio Frequency (RF) type Remote Keyless
Entry (RKE) system is standard factory-installed
equipment on this model. The RKE system allows
the use of a remote battery-powered radio transmit-
ter to control the power lock system. The RKE
receiver operates on non-switched battery current
through a fuse in the Power Distribution Center
(PDC), so that the system remains operational,
regardless of the ignition switch position.
In addition to Lock and Unlock buttons, the RKE
transmitters are also equipped with a Panic button.
If the Panic button on the RKE transmitter is
depressed, the horn will sound and the exterior lights
will flash on the vehicle for about three minutes, or
until the Panic button is depressed a second time, if
ignition is in the Off position. A vehicle speed of
about 24 kilometers-per-hour (15 miles-per-hour) will
also cancel the panic event.
The RKE system can also perform other functions
on this vehicle. If the vehicle is equipped with the
optional Vehicle Theft Security System (VTSS), the
RKE transmitter will arm the VTSS when the Lock
button is depressed, and disarm the VTSS when the
Unlock button is depressed. (Refer to 8 - ELECTRI-
CAL/VEHICLE THEFT SECURITY - DESCRIPTION
- VEHICLE THEFT SECURITY SYSTEM). If the
vehicle is equipped with the optional Memory Sys-
tem, each of the two numbered and color-coded RKE
transmitters can be used to recall the stored driver
side front seat position, both outside power rear view
mirror positions, and the radio station presets for the
two assigned drivers. (Refer to 8 - ELECTRICAL/
POWER SEATS - DESCRIPTION - MEMORY SYS-
TEM).
8N - 2 POWER LOCKSWJ
POWER LOCKS (Continued)

the engine compartment. This relay can be energized
by the BCM to sound the horns as an audible alert
for the RKE panic function and, if the Sound Horn
on Lock programmable feature is enabled, as an
audible verification for the RKE lock event. (Refer to
8 - ELECTRICAL/HORN/HORN RELAY - DESCRIP-
TION).
LOW BEAM HEADLAMP RELAY
The low beam headlamp relay is a electromechan-
ical device that switches battery current to the head-
lamp low beams when the BCM grounds the relay
coil. The low beam headlamp relay is located in the
junction block in the passenger compartment. This
relay can be energized by the BCM to flash the head-
lamp low beams as an optical alert for the RKE panic
function. (Refer to 8 - ELECTRICAL/LAMPS/LIGHT-
ING - EXTERIOR/HEADLAMP - DESCRIPTION).
DESCRIPTION - LIFTGATE FLIP-UP GLASS
POWER RELEASE SYSTEM
A power operated liftgate flip-up glass release sys-
tem is standard factory installed equipment on this
model. The liftgate flip-up glass power release system
allows the flip-up glass latch to be released electri-
cally by depressing a switch located on the bottom of
the liftgate license plate lamp housing unit, above
the license plate on the outside of the liftgate.
The liftgate flip-up glass release system operates
on non-switched battery current supplied through a
fuse in the junction block so that the system remains
functional, regardless of the ignition switch position.
However, a limit switch that is integral to the liftgate
latch actuator unit opens to prevent the flip-up glass
latch from being actuated when the liftgate latch is
locked.
The liftgate flip-up glass power release system
includes the following components:
²Liftgate Flip-Up Glass Limit Switch- The
liftgate flip-up glass limit switch is integral to the
liftgate latch unit. (Refer to 23 - BODY/DECKLID/
HATCH/LIFTGATE/TAILGATE/LATCH - REMOVAL)
and (Refer to 23 - BODY/DECKLID/HATCH/LIFT-
GATE/TAILGATE/LATCH - INSTALLATION).
²Liftgate Flip-Up Glass Release Motor- The
liftgate flip-up glass release motor is integral to the
liftgate flip-up glass latch unit. (Refer to 23 - BODY/
DECKLID/HATCH/LIFTGATE/TAILGATE/FLIP-UP
GLASS LATCH - REMOVAL) and (Refer to 23 -
BODY/DECKLID/HATCH/LIFTGATE/TAILGATE/
FLIP-UP GLASS LATCH - INSTALLATION).
²Liftgate Flip-Up Glass Release Switch- The
liftgate flip-up glass release switch is integral to the
liftgate license plate lamp housing. (Refer to 23 -
BODY/DECKLID/HATCH/LIFTGATE/TAILGATE/
FLIP-UP GLASS SWITCH - REMOVAL) and (Referto 23 - BODY/DECKLID/HATCH/LIFTGATE/TAIL-
GATE/FLIP-UP GLASS SWITCH - INSTALLATION).
Hard wired circuitry connects the liftgate flip-up
glass power release system components to the electri-
cal system of the vehicle. These hard wired circuits
are integral to several wire harnesses, which are
routed throughout the vehicle and retained by many
different methods. These circuits may be connected to
each other, to the vehicle electrical system and to the
liftgate flip-up glass power release system compo-
nents through the use of a combination of soldered
splices, splice block connectors, and many different
types of wire harness terminal connectors and insu-
lators. Refer to the appropriate wiring information.
The wiring information includes wiring diagrams,
proper wire and connector repair procedures, further
details on wire harness routing and retention, as well
as pin-out and location views for the various wire
harness connectors, splices and grounds.OPERATION
OPERATION - POWER LOCK SYSTEM
The Passenger Door Module (PDM) contains the
power door lock control logic and a power lock switch.
The Driver Door Module (DDM) contains a power
lock switch and controls the output to the driver side
front door power lock motor, while the PDM controls
the output to the power lock motors for the remain-
ing doors and the liftgate.
When the power lock switch on the DDM is used to
lock or unlock the doors, the DDM sends a control
output to the driver side front door power lock motor
and sends lock or unlock request messages to the
PDM over the Programmable Communications Inter-
face (PCI) data bus. The PDM responds to these mes-
sages by sending control outputs to the power lock
motors of the remaining doors and the liftgate. When
the power lock switch on the PDM is used to lock or
unlock the doors, the PDM sends control outputs to
the power lock motors in the passenger side front
door, both rear doors and the liftgate, then sends lock
or unlock request messages to the DDM over the Pro-
grammable Communications Interface (PCI) data
bus. The DDM responds to these messages by send-
ing control outputs to the power lock motor of the
driver side front door.
In order to support the auto door locks and unlock
on exit features, if enabled, the power lock system
logic in the PDM needs to know the door ajar switch
status, vehicle speed, and transmission gear selector
lever position. The passenger side front door ajar
switch is the only hard wired input to the PDM. The
PDM obtains the remaining information from mes-
sages it receives from other electronic modules over
the PCI data bus network.
8N - 4 POWER LOCKSWJ
POWER LOCKS (Continued)

²If the power lock system functions with the RKE
transmitter, but not with one or both power lock
switches, proceed to diagnosis of the door modules.
(Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/DOOR MODULE - DIAGNOSIS
AND TESTING).
²If the driver side power lock switch operates
only the driver side front door power lock motor, but
all other power lock motors operate with the passen-
ger side power lock switch or the RKE transmitter,
use a DRBIIItscan tool and the appropriate diagnos-
tic information to diagnose the Programmable Com-
munications Interface (PCI) data bus.
²If only one power lock motor fails to operate
with both power lock switches and the RKE trans-
mitter, proceed to diagnosis of the power lock motor.
(Refer to 8 - ELECTRICAL/POWER LOCKS/POWER
LOCK MOTOR - DIAGNOSIS AND TESTING).
DIAGNOSIS AND TESTING - REMOTE KEYLESS
ENTRY SYSTEM
Following are tests that will help to diagnose the
Remote Keyless Entry (RKE) system. However, these
tests may not prove conclusive in the diagnosis of
this system. In order to obtain conclusive testing of
the RKE system, the Programmable Communications
Interface (PCI) data bus network and all of the elec-
tronic modules that provide inputs to, or receive out-
puts from the RKE system components must be
checked.
The most reliable, efficient, and accurate means to
diagnose the RKE system requires the use of a
DRBIIItscan tool and the appropriate diagnostic
information. The DRBIIItscan tool can provide con-
firmation that the PCI data bus is functional, that all
of the electronic modules are sending and receiving
the proper messages on the PCI data bus, and that
the RKE receiver is being sent the proper radio fre-
quency signals by the RKE transmitters to perform
its RKE system functions.
Refer to the appropriate wiring information. The
wiring information includes wiring diagrams, proper
wire and connector repair procedures, details of wire
harness routing and retention, connector pin-out
information and location views for the various wire
harness connectors, splices and grounds.
PRELIMINARY DIAGNOSIS
As a preliminary diagnosis for the RKE system,
note the system operation while you perform both the
Lock and Unlock functions with the power lock
switches and with the Remote Keyless Entry (RKE)
transmitter. Then, proceed as follows:
²If the entire power lock system fails to function
with either the power lock switches or the RKE
transmitter, check the fused B(+) fuse in the PowerDistribution Center. If the fuse is OK, proceed to the
diagnosis for the door modules. (Refer to 8 - ELEC-
TRICAL/ELECTRONIC CONTROL MODULES/
DOOR MODULE - DIAGNOSIS AND TESTING).
²If the power lock system functions with both
power lock switches, but not with the RKE transmit-
ter, proceed to the diagnosis for the RKE transmitter.
(Refer to 8 - ELECTRICAL/POWER LOCKS/RE-
MOTE KEYLESS ENTRY TRANSMITTER - DIAG-
NOSIS AND TESTING).
²If the driver side power lock switch operates
only the driver side front door power lock motor, but
all other power lock motors operate with the passen-
ger side power lock switch or the RKE transmitter,
use a DRBIIItscan tool and the appropriate diagnos-
tic information to diagnose the Programmable Com-
munications Interface (PCI) data bus.
If the problem being diagnosed involves only the
Sound Horn on Lock or the Flash Lights with Locks
features, be certain that these programmable fea-
tures are enabled. If the features are enabled and the
service horn and turn signals still operate, the Body
Control Module (BCM) and the PCI data bus must be
tested. For diagnosis of the BCM or the PCI data
bus, the use of a DRBIII scan tool and the appropri-
ate diagnostic information are required.
DIAGNOSIS AND TESTING - LIFTGATE FLIP-UP
GLASS POWER RELEASE SYSTEM
Refer to the appropriate wiring information. The
wiring information includes wiring diagrams, proper
wire and connector repair procedures, details of wire
harness routing and retention, connector pin-out
information and location views for the various wire
harness connectors, splices and grounds.
(1) Check the fused B(+) fuse in the Junction
Block (JB). If OK, go to Step 2. If not OK, repair the
shorted circuit or component as required and replace
the faulty fuse.
(2) Check for battery voltage at the fused B(+) fuse
in the JB. If OK, go to Step 3. If not OK, repair the
open fused B(+) circuit to the Power Distribution
Center (PDC) as required.
(3) Disconnect the liftgate wire harness connector
for the liftgate lock motor and flip-up glass limit
switch from the motor and switch connector recepta-
cle. Check for battery voltage at the fused B(+) cir-
cuit cavity of the liftgate wire harness connector for
the liftgate lock motor and flip-up glass limit switch.
If OK, go to Step 4. If not OK, repair the open fused
B(+) circuit between the liftgate lock motor and
flip-up glass limit switch and the JB as required.
(4) Check for continuity between the two liftgate
flip-up glass limit switch terminals. There should be
continuity with the liftgate latch unlocked, and no
continuity with the latch locked. If OK, go to Step 5.
8N - 6 POWER LOCKSWJ
POWER LOCKS (Continued)

ULES/DRIVER DOOR MODULE - DESCRIPTION)
for more information.
²Passenger Door Module (PDM)(Refer to 8 -
ELECTRICAL/ELECTRONIC CONTROL MOD-
ULES/DRIVER DOOR MODULE - DESCRIPTION)
for more information.
Refer to the appropriate wiring information. The
wiring information includes wiring diagrams, proper
wire and connector repair procedures, details of wire
harness routing and retention, connector pin-out
information and location views for the various wire
harness connectors, splices and grounds.
OPERATION
The Driver Door Module (DDM) and the Passenger
Door Module (PDM) each contain the power mirror
control logic for the mirror on its respective door. The
DDM also houses the power mirror switch. Each door
module controls the positioning of its respective out-
side mirror through hard wired outputs to that mir-
ror. When the power mirror switch on the DDM is
used to position the passenger side outside mirror,
the DDM sends mirror positioning messages to the
PDM over the Programmable Communications Inter-
face (PCI) data bus. The PDM responds to these mes-
sages by sending control outputs to move the
passenger side mirror accordingly.
Both the PDM and DDM respond to the defogger
switch status messages sent by the Body Control
Module (BCM) over the PCI data bus to control the
electric heater grids of their respective mirrors.
(Refer to 8 - ELECTRICAL/HEATED MIRRORS -
DESCRIPTION) for more information on this fea-
ture.
On models equipped with the optional memory sys-
tem, each door module also receives a hard wired
input from the two power mirror motor position
potentiometers that are integral to each power mir-
ror. Each door module then stores the Driver 1 and
Driver 2 mirror position information for its respective
mirror. When the DDM receives a Driver 1 or Driver
2 memory recall message from the memory switch on
the driver side front door trim panel or from the
Remote Keyless Entry (RKE) receiver in the PDM,
the DDM positions the driver side mirror and sends
a memory recall message back to the PDM over the
PCI data bus to position the passenger side mirror.
See the owner's manual in the vehicle glove box for
more information on the features, use and operation
of the power mirror system.
DIAGNOSIS AND TESTING - POWER MIRRORS
Following are tests that will help to diagnose the
hard wired components and circuits of the power mir-
ror system. However, these tests may not prove con-
clusive in the diagnosis of this system. In order toobtain conclusive testing of the power mirror system,
the Programmable Communications Interface (PCI)
data bus network and all of the electronic modules
that provide inputs to, or receive outputs from the
power mirror system components must be checked.
The most reliable, efficient, and accurate means to
diagnose the power mirror system requires the use of
a DRB scan tool and the proper Diagnostic Proce-
dures manual. The DRB scan tool can provide confir-
mation that the PCI data bus is functional, that all
of the electronic modules are sending and receiving
the proper messages on the PCI data bus, that the
power mirror motors are being sent the proper hard
wired outputs, and that the mirror position potenti-
ometers are returning the proper outputs to the door
modules for them to perform their power mirror sys-
tem functions.
AUTOMATIC DAY/NIGHT
MIRROR
DESCRIPTION
DESCRIPTION - REAR VIEW MIRROR
An automatic day/night mirror system is an avail-
able factory-installed option on this model. The auto-
matic dimming inside day/night rear view mirror
system is a completely self-contained unit that
replaces the standard equipment inside rear view
mirror. This system will automatically change the
reflectance of the inside rear view mirror to protect
the driver from the unwanted headlight glare of
trailing vehicles while driving at night. The auto-
matic day/night inside mirror receives ignition
switched battery current through a fuse in the junc-
tion block, and will only operate when the ignition
switch is in the On position.
Vehicles equipped with the automatic day/night
mirror system are also available with an optional fac-
tory-installed automatic dimming outside rear view
mirror for the driver side of the vehicle. (Refer to 8 -
ELECTRICAL/POWER MIRRORS/SIDEVIEW MIR-
ROR - DESCRIPTION) for more information on this
option.
The automatic day/night mirror sensitivity cannot
be repaired or adjusted. If any component of this unit
is faulty or damaged, the entire automatic day/night
inside rear view mirror unit must be replaced. Refer
to the appropriate wiring information. The wiring
information includes wiring diagrams, proper wire
and connector repair procedures, details of wire har-
ness routing and retention, connector pin-out infor-
mation and location views for the various wire
harness connectors, splices and grounds.
8N - 12 POWER MIRRORSWJ
POWER MIRRORS (Continued)

DESCRIPTION - OUTSIDE REAR VIEW MIRROR
An automatic dimming outside rear view mirror is
an available factory-installed option for the driver
side of the vehicle, if the vehicle is also equipped
with the automatic day/night inside rear view mirror.
The automatic dimming outside mirror is completely
controlled by the circuitry of the automatic day/night
inside rear view mirror. The automatic dimming out-
side mirror will automatically change the reflectance
of the driver side outside rear view mirror to protect
the driver from the unwanted headlight glare of
trailing vehicles while driving at night. The auto-
matic dimming outside mirror will only operate when
the ignition switch is in the On position.
The automatic dimming outside mirror sensitivity
cannot be repaired or adjusted. If any component of
this unit is faulty or damaged, the entire automatic
dimming outside mirror unit must be replaced. (Refer
to 8 - ELECTRICAL/POWER MIRRORS/SIDEVIEW
MIRROR - DIAGNOSIS AND TESTING). Refer to
the appropriate wiring information. The wiring infor-
mation includes wiring diagrams, proper wire and
connector 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.
OPERATION
OPERATION - REAR VIEW MIRROR
The automatic day/night mirror switch allows the
driver a manual control of whether the automatic
dimming feature is operational. This switch is a
momentary rocker-type switch located on the lower
rear-facing surface of the mirror housing. When Auto
is selected, a Light-Emitting Diode (LED) on the mir-
ror housing just to the right of the switch illuminates
to indicate that automatic day/night mirror is turned
on. When Off is selected, the LED is turned off. The
mirror also senses the backup lamp circuit, and will
automatically disable its self-dimming feature when-
ever the transmission gear selector is in the Reverse
position.
A thin layer of electrochromatic material between
two pieces of conductive glass make up the face of
the mirror. Two photocell sensors are used to monitor
light levels and adjust the reflectance of the mirror.
The ambient photocell sensor faces forward, to detect
the outside light levels. The headlamp sensor is
located on the mirror housing just to the left of the
switch and facing rearward, to detect the light level
received at the rear window side of the mirror. When
the difference between the two light levels becomes
too great (the light level received at the rear of themirror is much higher than that at the front of the
mirror), the mirror begins to darken.
On models with an optional driver side automatic
dimming outside mirror, the signal to control the
dimming of that mirror is generated by the auto-
matic day/night inside rear view mirror circuitry.
That signal is then delivered to the driver side out-
side rear view mirror on a hard wired circuit.
See the owner's manual in the vehicle glove box for
more information on the features, use and operation
of the automatic day/night mirror system.
OPERATION - OUTSIDE REAR VIEW MIRROR
The automatic dimming outside mirror is operated
by the same controls and circuitry as the automatic
day/night mirror. When the automatic day/night mir-
ror is turned on or off, the automatic dimming out-
side mirror is likewise turned on or off. Like in the
automatic day/night mirror, a thin layer of electro-
chromatic material between two pieces of conductive
glass make up the face of the automatic dimming
outside mirror. However, the signal to control the
dimming of the outside mirror is generated by the
automatic day/night inside rear view mirror circuitry.
See the owner's manual in the vehicle glove box for
more information on the features, use and operation
of the automatic dimming outside mirror.
DIAGNOSIS AND TESTING - AUTOMATIC DAY /
NIGHT MIRROR
For complete circuit diagrams, refer to the appro-
priate wiring information. The wiring information
includes wiring diagrams, proper wire and connector
repair procedures, details of wire harness routing
and retention, connector pin-out information and
location views for the various wire harness connec-
tors, splices and grounds.
(1) Check the fused ignition switch output (run/
start) fuse in the junction block. If OK, go to Step 2.
If not OK, repair the shorted circuit or component as
required and replace the faulty fuse.
(2) Turn the ignition switch to the On position.
Check for battery voltage at the fused ignition switch
output (run/start) fuse in the junction block. If OK,
go to Step 3. If not OK, repair the open fused ignition
switch output (run/start) circuit to the ignition switch
as required.
(3) Disconnect the overhead wire harness connec-
tor from the automatic day/night mirror connector
receptacle. Check for battery voltage at the fused
ignition switch output (run/start) circuit cavity of the
overhead wire harness connector for the automatic
day/night mirror. If OK, go to Step 4. If not OK,
repair the open fused ignition switch output (run/
start) circuit to the fuse in the junction block as
required.
WJPOWER MIRRORS 8N - 13
AUTOMATIC DAY/NIGHT MIRROR (Continued)