
ELECTRICALLY HEATED SYSTEMS
CONTENTS
page page
DESCRIPTION AND OPERATION
HVAC MOUNTED SWITCH................. 1
INTRODUCTION......................... 1
DIAGNOSIS AND TESTING
GRID LINE TEST......................... 2SYSTEM TEST.......................... 2
SERVICE PROCEDURES
GRID LINE AND TERMINAL REPAIR......... 3
DESCRIPTION AND OPERATION
INTRODUCTION
The electrically heated Rear Window Defogger (Fig.
1), Heated Power Side View Mirrors, and Heated
Windshield Wiper De-icer (Fig. 2) is available on NS
vehicles.
The Rear Window Defogger system consists of two
vertical bus bars linked by a series of grid lines on
the inside surface of the rear window. The electrical
circuit consists of the rear defogger switch in the
HVAC and a relay with timer switch to turn OFF the
system after ten minutes. The main feed circuit is
protected by fuse one (40 amp) in the Junction Block.
The rear defogger switch and relay also activates the
heated power side view mirrors and heated wind-
shield wiper de-icer. The HVAC rear defogger switch
is protected by fuse ten (10 amp) in the Junction
Block. The heated mirror circuit is protected by fuse
12 (10 amp) in the junction block. The heated wind-
shield wiper de-icer circuit is protected by fuse 21 (25
amp) in the Junction Block.
The Heated Windshield Wiper Deicer is also acti-
vated when the DEFROST mode is selected on the
HVAC. In the DEFROST mode the rear defogger
relay/timer is bypassed, the heated windshield wiper
de-icer will stay ON until the another mode is
selected. For circuit information and component loca-
tion refer to Group 8W, Wiring Diagrams.
CAUTION: Since grid lines can be damaged or
scraped off with sharp instruments, care should be
taken in cleaning the glass or removing foreign
materials, decals or stickers. Normal glass cleaning
solvents or hot water used with rags or toweling is
recommended.
HVAC MOUNTED SWITCH
The rear window defogger switch is integrated into
the HVAC (Fig. 3). An LED indicator will illuminate
when the switch is activated. The switch energizesthe timing circuit and activates the rear window
defogger relay. The relay controls the current to flow
to the grids of the rear window defogger, heated
power side view mirrors and the heated windshield
wiper de-icer. The defogger relay will be on for
approximately 10 minutes or until the control switch
or ignition is turned off.
Fig. 1 Rear Window Defogger
Fig. 2 Heated Windshield Wiper De-icer
NSELECTRICALLY HEATED SYSTEMS 8N - 1

DIAGNOSIS AND TESTING
SYSTEM TEST
Electrically heated rear window defogger or the
heated windshield wiper deicer operation can be
checked on the vehicle in the following manner:
(1) Turn the ignition switch to the ON position.
(2) Using a ammeter on the battery, turn the rear
defogger control switch to the ON position, a distinct
increase in amperage draw should be noted.
(3) The rear window defogger or the heated wind-
shield wiper deicer operation can be checked by feel-
ing the glass. A distinct difference in temperature
between the grid lines and adjacent clear glass can
be detected in 3 to 4 minutes of operation.
(4) Using a DC voltmeter (Fig. 4) contact terminal
B with the negative lead, and terminal A with the
positive lead. The voltmeter should read 10-14 volts.
(5) Indicator light illumination means that there is
power available at the switch only and does not nec-
essarily verify system operation.
(6) If turning the defogger switch ON, no distinct
current draw on the ammeter the problem should be
isolated in the following manner:
²Confirm that ignition switch is ON.
²Ensure that the heated rear window or the
heated windshield wiper deicer feed pigtail is con-
nected to the wiring harness and that the ground
pigtail is in fact grounded.
²Ensure that the proper fuse in the Junction
Block is OK.(7) When the above steps have been completed and
the system is still inoperative, one or more of the fol-
lowing is defective:
²HVAC switch
²Rear window defogger relay in the relay bank.
²Check for loose connector or a wire pushed out
of connector.
²Rear window or the windshield grid lines (all
grid lines would have to be broken, or one of the feed
pigtails not connected to the bus bar, for no ammeter
deflection).
(8) If turning the switch ON produces severe volt-
meter deflection, the circuit should be closely checked
for a shorting condition.
(9) If the system operation has been verified but
indicator LED does not light, replace switch.
(10) For detailed wiring information, refer to
Group 8W, Wiring Diagrams.
GRID LINE TEST
The horizontal grid lines and vertical bus bar lines
printed and baked on inside surface of the window
glass makes up an electrical parallel circuit. The
electrically conductive lines are composed of a silver
ceramic material which when baked on glass
becomes bonded to the glass and is highly resistant
to abrasion. It is possible, however, that a break may
exist or occur in an individual grid line resulting in
no current flow through the line. To detect breaks in
grid lines, the following procedure is required:
(1) Turn ignition and rear window defogger control
switch ON. The indicator light should come on.
(2) Using a DC voltmeter with 0-15 volt range,
contact vertical bus bar connecting grid lines on pas-
senger side of vehicle at terminal A with negative
lead of voltmeter (Fig. 4). With positive lead of volt-
meter, contact vertical bus bar on driver side of vehi-
cle at terminal B. The voltmeter should read 10-14
volts.
Fig. 3 HVAC Rear Window Defogger Switch
Fig. 4 Grid Line Test
8N - 2 ELECTRICALLY HEATED SYSTEMSNS
DIAGNOSIS AND TESTING (Continued)

WIRING DIAGRAMS
CONTENTS
page page
AIR CONDITIONING-HEATER.......... 8W-42-1
AIRBAG SYSTEM................... 8W-43-1
ANTI-LOCK BRAKES................. 8W-35-1
AUDIO SYSTEM.................... 8W-47-1
BODY CONTROL MODULE............ 8W-45-1
CHARGING SYSTEM................. 8W-20-1
COMPONENT INDEX................. 8W-02-1
CONNECTOR/GROUND LOCATIONS..... 8W-90-1
CONNECTOR PIN-OUTS.............. 8W-80-1
FRONT LIGHTING................... 8W-50-1
FUEL/IGNITION SYSTEM............. 8W-30-1
GENERAL INFORMATION............. 8W-01-1
GROUND DISTRIBUTION............. 8W-15-1
HORN/CIGAR LIGHTER/POWER OUTLET . 8W-41-1
INSTRUMENT CLUSTER.............. 8W-40-1
INTERIOR LIGHTING................. 8W-44-1
JUNCTION BLOCK................... 8W-12-1
MESSAGE CENTER.................. 8W-46-1OVERHEAD CONSOLE................ 8W-49-1
POWER DISTRIBUTION.............. 8W-10-1
POWER DOOR LOCKS............... 8W-61-1
POWER MIRRORS.................. 8W-62-1
POWER SEAT...................... 8W-63-1
POWER WINDOWS.................. 8W-60-1
REAR LIGHTING.................... 8W-51-1
SPLICE INFORMATION............... 8W-70-1
SPLICE LOCATIONS................. 8W-95-1
STARTING SYSTEM................. 8W-21-1
TRAILER TOW...................... 8W-54-1
TRANSMISSION CONTROL SYSTEM.... 8W-31-1
TURN SIGNALS..................... 8W-52-1
VEHICLE SPEED CONTROL........... 8W-33-1
VEHICLE THEFT SECURITY SYSTEM.... 8W-39-1
WINDOW DEFOGGERS............... 8W-48-1
WIPERS........................... 8W-53-1
NS/GSWIRING DIAGRAMS 8W - 1

CIRCUIT INFORMATION
Each wire shown in the diagrams contains a code
which identifies the main circuit, part of the main
circuit, gage of wire, and color (Fig. 1).
CIRCUIT FUNCTIONS
All circuits in the diagrams use an alpha/numeric
code to identify the wire and its function. To identify
which circuit code applies to a system, refer to the
Circuit Identification Code Chart. This chart shows
the main circuits only and does not show the second-
ary codes that may apply to some models.
Fig. 1 Wire Code Identification
COLOR CODE COLORSTANDARD
TRACER
COLOR
BL BLUE WT
BK BLACK WT
BR BROWN WT
DB DARK BLUE WT
DG DARK GREEN WT
GY GRAY BK
LB LIGHT BLUE BK
LG LIGHT GREEN BK
OR ORANGE BK
PK PINK BK or WT
RD RED WT
TN TAN WT
VT VIOLET WT
WT WHITE BK
YL YELLOW BK
* WITH TRACER
CIRCUIT FUNCTION
A BATTERY FEED
B BRAKE CONTROLS
C CLIMATE CONTROLS
D DIAGNOSTIC CIRCUITS
E DIMMING ILLUMINATION CIRCUITS
F FUSED CIRCUITS
G MONITORING CIRCUITS (GAUGES)
H OPEN
I NOT USED
J OPEN
K POWERTRAIN CONTROL MODULE
L EXTERIOR LIGHTING
M INTERIOR LIGHTING
N NOT USED
O NOT USED
P POWER OPTION (BATTERY FEED)
Q POWER OPTIONS (IGNITION FEED)
R PASSIVE RESTRAINT
S SUSPENSION/STEERING
T TRANSMISSION/TRANSAXLE/
TRANSFER CASE
U OPEN
V SPEED CONTROL, WIPER/WASHER
W OPEN
X AUDIO SYSTEMS
Y OPEN
Z GROUNDS
8W - 01 - 4 8W-01 GENERAL INFORMATIONNS/GS
DESCRIPTION AND OPERATION (Continued)

SECTION IDENTIFICATION
The wiring diagrams are grouped into individual
sections. If a component is most likely found in a par-
ticular group, it will be shown complete (all wires,
connectors, and pins) within that group. For exam-
ple, the Auto Shutdown Relay is most likely to be
found in Group 30, so it is shown there complete. It
can, however, be shown partially in another group if
it contains some associated wiring.
SYMBOLS
International symbols are used throughout the wir-
ing diagrams. These symbols are consistent with
those being used around the world.
GROUP TOPIC
8W-01 thru 8W-09 General Information and
Diagram Overview
8W-10 thru 8W-19 Main Sources of Power and
Vehicle Grounding
8W-20 thru 8W-29 Starting and Charging
8W-30 thru 8W-39 Powertrain/Drivetrain
Systems
8W-40 thru 8W-49 Body Electrical items and A/C
8W-50 thru 8W-59 Exterior Lighting, Wipers, and
Trailer Tow
8W-60 thru 8W-69 Power Accessories
8W-70 Splice Information
8W-80 Connector Pin Outs
8W-90 Connector Locations
(including grounds)
8W-95 Splice Locations
NS/GS8W-01 GENERAL INFORMATION 8W - 01 - 5
DESCRIPTION AND OPERATION (Continued)

8W-02 COMPONENT INDEX
Component Page
2-4 Pressure Switch.....................8W-31
2-4 Solenoid...........................8W-31
A/C Compressor Clutch..................8W-42
A/C Compressor Clutch Relay...........8W-10, 42
A/C Heater Control.....................8W-42
A/C On Indicator.......................8W-42
A/C Pressure Transducer..............8W-30, 42
A/C Switch............................8W-42
A/C Zone Door Actuator..................8W-42
ABS Warning Lamp..................8W-35, 46
Accelerator Pedal Position Sensor..........8W-30
Airbag Control Module...................8W-43
Airbag Indicator Lamp...................8W-43
Airbag Warning Lamp...................8W-46
All Wheel Drive Solenoid.................8W-31
Ambient Air Temperature Sensor...........8W-49
Ash Receiver Lamp.....................8W-44
Automatic Day/Night Mirror..............8W-44
Automatic Shut Down Relay............8W-10, 30
Splice Information......................8W-70
Back-Up Lamp.........................8W-51
Back-Up Switch.....................8W-44, 51
Battery...............................8W-20
Blend Door Actuator.....................8W-42
Body Control Module....................8W-45
Brake Pressure Switch...................8W-46
Brake Warning Lamp....................8W-46
Camshaft Position Sensor................8W-30
Center Dome Lamp.....................8W-44
Center High Mounted Stop Lamp..........8W-51
Cigar/Accessory Relay...................8W-41
Clockspring.......8W-10, 15, 30, 33, 39, 40, 41, 43
Cluster Illumination Lamps...............8W-40
Clutch Interlock Switch...............8W-12, 21
Clutch Interlock Switch Jumper......8W-12, 21, 31
Clutch Switch.......................8W-30, 33
Combination Flasher/DRL Module. . . .8W-50, 51, 52
Combination Relays.....................8W-54
Compass/Mini-Trip Computer..............8W-49
Control Sleeve Sensor....................8W-30
Controller Anti-Lock Brake...............8W-35
Courtesy Lamp Relay...........8W-10, 12, 44, 50
Crank Case Heater......................8W-30
Crankshaft Position Sensor...............8W-30
Cruise Indicator Lamp...................8W-40
Data Link Connector....................8W-30
Diesel Power Relay...................8W-10, 30
Dome Lamp Switch.....................8W-50
Door Ajar Indicator Lamp................8W-40
Door Ajar Switches................8W-39, 40, 44
Door Lock Relay........................8W-61
Speakers..............................8W-47Component Page
Door Unlock Relay......................8W-61
Oxygen Sensors........................8W-30
Door Ajar Switches.............8W-39, 40, 44, 45
Door Arm/Disarm Switches.............8W-39, 61
Door Courtesy Lamps....................8W-44
Door Lock Motors.......................8W-61
Door Lock Switches.....................8W-61
Door Unlock Relays.....................8W-61
Heated Seat Backs......................8W-63
Heated Seat Cushions...................8W-63
Heated Seat Modules....................8W-63
Heated Seat Switches....................8W-63
Power Mirrors.........................8W-62
Power Seat Switches....................8W-63
Power Window Switches..................8W-60
Seat Motors...........................8W-63
Window Motors........................8W-60
Radiator Fans.........................8W-42
Dump Solenoid.........................8W-33
EGR Solenoid..........................8W-30
Electric Wiper De-Icer...................8W-48
Electronic PRNDL Indicator...............8W-40
Engine Coolant Temperature Gauge.........8W-40
Engine Coolant Temperature Lamp.........8W-46
Engine Coolant Temperature Sensor........8W-30
Engine Oil Pressure Switch...............8W-46
Engine Speed Sensor....................8W-30
Engine Starter Motor....................8W-21
Engine Starter Motor Relay............8W-10, 21
Evap Leak Detection Pump...............8W-30
Evap/Purge Solenoid....................8W-30
Evaporator Temperature Sensor............8W-42
Express Down Module...................8W-60
Flexible Fuel Sensor.....................8W-30
Fog Lamps............................8W-50
Fog Lamp Relay........................8W-50
Front Blower Motor.....................8W-42
Front Blower Motor Relay.............8W-10, 42
Front Blower Motor Resistor Block.........8W-42
Front Cigar Lighter/Power Outlet..........8W-41
Front Reading Lamp Defeat Switch.........8W-44
Front Reading Lamps/Switch..............8W-44
Front Washer Motor.....................8W-53
Front Wiper Switch.....................8W-53
Fuel Gauge............................8W-40
Fuel Heater...........................8W-30
Fuel Heater Relay...................8W-10, 30
Fuel Injectors..........................8W-30
Fuel Pump Module......................8W-30
Fuel Pump Relay....................8W-10, 30
Fuel Quantity Actuator..................8W-30
Fuel Shutdown Solenoid..................8W-30
NS/GS8W - 02 COMPONENT INDEX 8W - 02 - 1

Component Page
Fuel Tank Module...................8W-30, 45
Fuel Temperature Sensor.................8W-30
Fuel Timing Solenoid....................8W-30
Fuses (JB)............................8W-12
Fuses (PDC)...........................8W-10
Fusible Link.....................8W-20, 21, 63
Fusible Link A0........................8W-30
Fusible Link A11.......................8W-10
Fusible Link A54.......................8W-10
Grounds..............................8W-15
Generator.............................8W-20
Glove Box Lamp........................8W-44
Glow Plug Lamp.....................8W-30, 46
Glow Plugs............................8W-30
Glow Plug Relay........................8W-30
Headlamps............................8W-50
Headlamp Dimmer Switch..........8W-10, 46, 50
Headlamp Leveling Motors...............8W-50
Headlamp Switch.......................8W-50
Headlamp Washer......................8W-53
High Beam Indicator....................8W-46
High Beam Relay....................8W-10, 50
Headlamps............................8W-50
Horns................................8W-41
Hood Ajar Switch....................8W-39, 44
Horn Relay.........................8W-39, 41
Horn Switch.....................8W-10, 39, 41
HVAC Control.........................8W-42
Idle Air Control Motor...................8W-30
Ignition Coil Pack.......................8W-30
Ignition Switch.........................8W-10
Instrument Cluster.....................8W-40
Intake Air Temperature Sensor............8W-30
Intake Air Temperature/Manifold Absolute
Pressure Sensor.....................8W-30
Interior Lamps On Switch................8W-44
Junction Block.........................8W-12
Key-In Halo Lamp......................8W-44
Knock Sensor..........................8W-30
Lamp Assemblies.......................8W-51
License Lamp..........................8W-51
Liftgate Ajar Indicator Lamp..............8W-40
Liftgate Ajar Switch...............8W-39, 40, 44
Liftgate Arm/Disarm Switch............8W-39, 61
Liftgate Flood Lamps....................8W-44
Liftgate Lock Motor.....................8W-61
Low Beam Relay.....................8W-10, 50
Low Coolant Level Switch................8W-45
Low Fuel Warning Indicator Lamp..........8W-40
Low Oil Pressure Lamp..................8W-46
Low Washer Fluid Level Indicator Lamp.....8W-40
Low Washer Fluid Switch.................8W-53
Low/Reverse Pressure Switch..............8W-31
Low/Reverse Solenoid....................8W-31Component Page
Manifold Absolute Pressure Sensor.........8W-30
Memory Power Seat Switch...............8W-63
Seat Sensors...........................8W-63
Memory Seat/Mirror Module...........8W-62, 63
Memory Set Switch..................8W-62, 63
Message Center........................8W-46
Mid Reading Lamps.....................8W-44
Mode Door Actuator.....................8W-42
Name Brand Speaker Relay...............8W-47
Needle Movement Sensor.................8W-30
Odometer.............................8W-40
Output Shaft Speed Sensor...............8W-31
Overdrive Pressure Switch................8W-31
Overdrive Solenoid......................8W-31
Overhead Console.......................8W-49
Park Brake Switch...................8W-46, 50
Park Lamp Relay.........8W-10, 12, 44, 50, 51, 54
Park/Turn Signal Lamps.................8W-50
Airbag Squibs..........................8W-43
Power Distribution Center................8W-10
Power Folding Mirror Switch..............8W-62
Power Mirror Fold Relay.................8W-62
Power Mirror Switch....................8W-62
Power Mirror Unfold Relay...............8W-62
Power Seat Circuit Breaker............8W-62, 63
Powertrain Control Module...............8W-30
PTCs (JB).............................8W-12
Radiator Fan Disconnect.................8W-42
Radiator Fan Relays.....................8W-42
Radio................................8W-47
Radio Choke...........................8W-47
Reading Lamps........................8W-44
Rear A/C Heater Unit....................8W-42
Rear Blower Control Switches.............8W-42
Rear Cigar Lighter/Power Outlet...........8W-41
Rear Defogger On Indicator...............8W-42
Rear Dome Lamp.......................8W-44
Rear Fog Lamp.........................8W-51
Rear Fog Lamp Indicator.................8W-51
Rear Washer Motor.....................8W-53
Rear Washer Switch..................8W-42, 53
Rear Window Defogger...................8W-48
Rear Window Defogger Relay..............8W-48
Rear Window Defogger Switch..........8W-42, 48
Rear Wiper Delay On Indicator.........8W-42, 53
Rear Wiper Delay Switch..............8W-42, 53
Rear Wiper Motor.......................8W-53
Rear Wiper On Indicator..............8W-42, 53
Rear Wiper On Switch................8W-42, 53
Recirculate Mode Indicator................8W-42
Recirculate Mode Switch.................8W-42
Recirculation Door Actuator...............8W-42
Remote Keyless Entry Module.............8W-61
Repeater Lamps.....................8W-51, 52
8W - 02 - 2 8W - 02 COMPONENT INDEXNS/GS

Component Page
Seat Belt Indicator Lamp.................8W-40
Seat Belt Switch........................8W-40
Sentry Key Immobilizer Module............8W-39
Service Engine Soon Lamp.............8W-30, 46
Sliding Door Contacts....................8W-61
Sliding Door Lock Motors.................8W-61
Speed Control Switches...............8W-30, 33
Speedometer...........................8W-40
Stop Lamp Switch...................8W-33, 51
Stop/Turn Signal Relays..................8W-54
Tachometer............................8W-40
Tail/Stop Lamp.........................8W-51
Tail/Turn Signal Lamp................8W-51, 52
Throttle Position Sensor..................8W-30
Traction Control Switch..................8W-35
Trailer Tow Connector...................8W-54
Transmission Control Module..............8W-31
Transmission Control Relay............8W-10, 31
Transmission Control Solenoids............8W-31
Transmission Range Sensor...............8W-31
Trip Odometer.........................8W-40Component Page
Turbine Speed Sensor....................8W-31
Turbo Boost Pressure Sensor..............8W-30
Turn Indicators......................8W-46, 52
Turn Signal/Hazard Switch............8W-46, 52
Underdrive Solenoid.....................8W-31
Universal Garage Door Opener............8W-49
Vacuum Solenoid.......................8W-33
Vehicle Speed Control Servo...............8W-33
Vehicle Speed Sensor....................8W-30
Vent Motors...........................8W-60
Vent Solenoids.........................8W-33
Visor/Vanity Mirror Lamps................8W-44
Voltage Regulator.......................8W-20
Volts Indicator Lamp....................8W-40
VTSS Lamp........................8W-39, 46
Washer Module.........................8W-53
Wheel Speed Sensors....................8W-35
Wiper High/Low Relay...................8W-53
Wiper Module..........................8W-53
Wiper On Relay........................8W-53
NS/GS8W - 02 COMPONENT INDEX 8W - 02 - 3