diagram MERCEDES-BENZ SPRINTER 2006 Owners Manual

(6) Rotate and hold ignition switch in Start posi-
tion. Note cranking voltage and current (amperage)
draw readings shown on volt-ampere tester.
(a) If voltage reads below 9.6 volts, refer to
Starter Motorin Diagnosis and Testing. If starter
motor is OK, refer toEngine Diagnosisin 9,
Engine for further testing of engine. If starter
motor is not OK, replace faulty starter motor.
(b) If voltage reads above 9.6 volts and current
(amperage) draw reads below specifications, refer
toFeed Circuit Testin this section.
(c) If voltage reads 12.5 volts or greater and
starter motor does not turn, refer toControl Cir-
cuit Testingin this section.
(d) If voltage reads 12.5 volts or greater and
starter motor turns very slowly, refer toFeed Cir-
cuit Testin this section.
NOTE: A cold engine will increase starter current
(amperage) draw reading, and reduce battery volt-
age reading.
FEED CIRCUIT TEST
The starter feed circuit test (voltage drop method)
will determine if there is excessive resistance in
high-amperage feed circuit. For complete starter wir-
ing circuit diagrams, refer 8, Wiring Diagrams.
When performing these tests, it is important to
remember that voltage drop is giving an indication of
resistance between two points at which voltmeter
probes are attached.
Example:When testing resistance of positive bat-
tery cable, touch voltmeter leads to positive battery
cable clamp and cable connector at starter solenoid.
If you probe positive battery terminal post and cable
connector at starter solenoid, you are reading com-
bined voltage drop in positive battery cable clamp-to-
terminal post connection and positive battery cable.
The following operation will require a voltmeter
accurate to 1/10 (0.10) volt. Before performing tests,
be certain that following procedures are accom-
plished:
²Battery is fully-charged and load-tested. Refer to
Batteryin 8, Battery.
²Fully engage parking brake.
²Place gearshift selector lever in Park position.
²Verify that all lamps and accessories are turned
off.
²To prevent engine from starting, remove Fuel
Pump Relay. This relay is located in Power Distribu-
tion Center (PDC). Refer to label on PDC cover for
relay location.
(1) Connect positive lead of voltmeter to negative
battery cable terminal post. Connect negative lead of
voltmeter to negative battery cable clamp (Fig. 2).
Rotate and hold ignition switch in Start position.
Observe voltmeter. If voltage is detected, correct poorcontact between cable clamp and terminal post.
(2) Connect positive lead of voltmeter to positive
battery terminal post. Connect negative lead of volt-
meter to battery positive cable clamp (Fig. 3). Rotate
and hold ignition switch in Start position. Observe
voltmeter. If voltage is detected, correct poor contact
between cable clamp and terminal post.
(3) Connect voltmeter to measure between battery
positive terminal post and starter solenoid battery
terminal stud (Fig. 4). Rotate and hold ignition
switch in Start position. Observe voltmeter. If read-
ing is above 0.2 volt, clean and tighten battery cable
connection at solenoid. Repeat test. If reading is still
above 0.2 volt, replace faulty positive battery cable.
Fig. 2 TEST NEGATIVE BATTERY CABLE
CONNECTION RESISTANCE - TYPICAL
1 - VOLTMETER
2 - BATTERY
Fig. 3 TEST POSITIVE BATTERY CABLE
CONNECTION RESISTANCE - TYPICAL
1 - VOLTMETER
2 - BATTERY
VASTARTING SYSTEM 8F - 31

(4) Connect voltmeter to measure between nega-
tive battery terminal post and a good clean ground
on engine block (Fig. 5). Rotate and hold ignition
switch in Start position. Observe voltmeter. If read-
ing is above 0.2 volt, clean and tighten negative bat-
tery cable attachment on engine block. Repeat test. If
reading is still above 0.2 volt, replace faulty negative
battery cable.(5) Connect positive lead of voltmeter to starter
housing. Connect negative lead of voltmeter to nega-
tive battery terminal post (Fig. 6). Rotate and hold
ignition switch in Start position. Observe voltmeter.
If reading is above 0.2 volt, correct poor starter to
engine block ground contact.
If resistance tests detect no feed circuit problems,
refer toStarter Motorin the Diagnosis and Testing.
CONTROL CIRCUIT TESTING
The starter control circuit components should be
tested in the order in which they are listed, as fol-
lows:
²Starter Relay- Refer toStarter RelayDiag-
nosis and Testing.
²Starter Solenoid- Refer toStarter Motor
Diagnosis and Testing.
²Ignition Switch- Refer toIgnition Switch
and Key Lock Cylinder
²Park/Neutral Position Switch- If equipped
with automatic transmission, refer toPark/Neutral
Position Switchin 21, Transmission.
²Wire harnesses and connections- Refer to 8,
Wiring Diagrams.
Fig. 4 TEST POSITIVE BATTERY CABLE
1 - BATTERY
2 - VOLTMETER
3 - STARTER MOTOR
Fig. 5 TEST GROUND CIRCUIT RESISTANCE -
TYPICAL
1 - VOLTMETER
2 - BATTERY
3 - ENGINE GROUND
Fig. 6 TEST STARTER GROUND - TYPICAL
1 - STARTER MOTOR
2 - BATTERY
3 - VOLTMETER
8F - 32 STARTING SYSTEMVA

relays which allows battery current to flow to the
rear window defogger grid lines. The heated grid
lines heat the rear glass to help clear the rear win-
dow surfaces of fog or frost.
The electric backlight (EBL) system is controlled
by the EBL timing circuity, which is integral to the
rear window defogger module. A yellow indicator in
the switch will illuminate to indicate when the EBL
system is turned on.
NOTE: The EBL system turns off automatically after
approximately 10 minutes of initial operation. Each
following activation cycle of the EBL system will
last approximately five minutes.
The EBL system will be automatically turned off
after a programmed time interval of about ten min-
utes. After the initial time interval has expired, if the
rear window defogger switch is pressed to the On
position again during the same ignition cycle, the
EBL system will automatically turn off after about
five minutes.
The EBL system will automatically shut off if the
ignition switch is turned to the Off position, or it can
be turned off manually by pressing the defogger
switch a second time.
DIAGNOSIS AND TESTING
ELECTRIC BACKLIGHT (EBL) SYSTEM
NOTE: Illumination of the defogger switch indicator
lamp means that there is electrical current available
at the output of the rear window defogger logic cir-
cuitry, but does not confirm that the electrical cur-
rent is reaching the rear glass heating grid lines.
NOTE: For circuit descriptions and diagrams of the
EBL system, refer to 8W - WIRING DIAGRAM
INFORMATION.
Operation of the electrical backlight (EBL) system
can be confirmed by the following:
(1) Turn the ignition switch to the On position. Set
the rear window defogger switch in the On position.
The rear window defogger operation can be checked
by feeling the rear window glass. A distinct difference
in temperature between the grid lines and the adja-
cent clear glass should be detected within three to
four minutes of operation.
(2) If a temperature difference is not detected, use
a 12-volt DC voltmeter and contact the rear glass
heating grid terminal B with the negative lead, and
terminal A with the positive lead (Fig. 2). The volt-
meter should read battery voltage. If the voltmeter
does not read battery voltage, check the following:²Confirm that the ignition switch is in the On
position.
²Make sure that the rear glass heating grid feed
wires and ground wires are connected to the window
terminals. Confirm that the ground wires have conti-
nuity to ground.
²Check that fuse 7 (15 amp) in fuse block #1 and
fuse 10 (30 amp) in the fuse/relay block are OK. The
fuses must be tight in there receptacles and all elec-
trical connections must be secure.
(3) When the above steps have been completed and
the rear glass heating grid is still inoperative, one or
more of the following is faulty.
²Rear window defogger switch in the instrument
panel.
²Rear window defogger (EBL) relays in the fuse/
relay block.
²Rear window defogger (EBL) relay control circu-
ity in the rear window defogger module.
²Check for a loose wire connector or a wire
pushed out of a connector.
²Rear window grid lines (all grid lines would
have to be broken, or the power feed or ground wire
not connected, for the entire heating grid to be inop-
erative).
(4) If the system operation has been verified but
the defogger switch indicator does not illuminate,
check for voltage at the defogger indicator from the
rear window defogger module when the defogger
switch is activated. If power is present, replace the
rear window defogger switch.
(5) If broken defogger grid lines are suspected, use
a 12-volt DC voltmeter and contact terminal B with
the negative lead and each rear glass heating grid
line at it's mid-point with the positive lead. The volt-
meter should read approximately 6 volts at each grid
line mid-point C. If the voltmeter does not read
approximately 6 volts, repair the open grid line(s)
(Refer to 8 - ELECTRICAL/HEATED GLASS/REAR
WINDOW DEFOGGER GRID - STANDARD PROCE-
DURE).
8G - 2 HEATED GLASSVA

²The coil ground terminal (86) is hardwired to
ground point G202.
²The coil battery terminal (85) receives a battery
current input from the rear window defogger module
when the rear window defogger switch is energized.
²The normally open terminal (87) provides a bat-
tery current output to the rear window defogger grid
lines through the relay output circuit only when the
rear window defogger relay coil is energized.
²The normally closed terminal (87A) is not con-
nected to any circuit in this application, but provides
a battery current output only when the rear window
defogger relay coil is de-energized.
The left and right EBL relays cannot be repaired
and, if faulty or damaged, they must be replaced.
Refer to the appropriate wiring information for diag-
nosis and testing of the EBL relays and for complete
rear window defogger system wiring diagrams.
REMOVAL
(1) Disconnect and isolate the negative battery
cable.
(2) Remove the cover from the fuse/relay block
(Fig. 4).
NOTE: Refer to the fuse and relay map located on
the inner surface of the fuse/relay block cover for
the left and right rear window defogger (EBL) relay
locations.
(3) Remove the EBL relays from the fuse/relay
block as required.
INSTALLATION
NOTE: Refer to the fuse and relay map located on
the inner surface of the fuse/relay block cover for
the left and right rear window defogger (EBL) relay
locations.
(1) Position the rear window defogger (EBL) relays
as required into their proper receptacles in the fuse/
relay block.
(2) Align the EBL relay terminals with the termi-
nal cavities in the fuse/relay block receptacles.
(3) Push down firmly on the EBL relays until the
terminals are fully seated in the terminal cavities in
the fuse/relay block receptacles.
(4) Install the cover onto the fuse/relay block.
(5) Reconnect the negative battery cable.
REAR WINDOW DEFOGGER
SWITCH
DESCRIPTION
The rear window defogger switch is mounted in the
instrument panel to the right of the steering wheel
(Fig. 5). The rear window defogger switch contains a
yellow indicator lamp that illuminates when the rear
window defogger (EBL) system is activated.
The rear window defogger switch and the defogger
switch indicator cannot be repaired and, if faulty or
damaged, the rear window defogger switch must be
replaced.
OPERATION
A yellow indicator lamp will illuminate when the
rear window defogger switch is activated. The switch
Fig. 4 Rear Window Defogger (EBL) Relays
1 - DRIVERS SEAT
2 - FUSE/RELAY BLOCKFig. 5 Rear Window Defogger Switch
1 - REAR WINDOW DEFOGGER SWITCH
2 - INSTRUMENT PANEL
8G - 4 HEATED GLASSVA

energizes the timing circuit of the rear window defog-
ger module which then activates the rear window
defogger (EBL) relays. The EBL relays controls the
current flow to the rear window defogger grids. The
EBL system will operate for approximately five min-
utes or until the rear window defogger switch or igni-
tion switch is turned off. Refer to 8 - ELECTRICAL/
HEATED GLASS - DIAGNOSIS AND TESTING for
diagnosis and testing of the rear window defogger
switch.
The rear window defogger switch cannot be
repaired and, if faulty or damaged, it must be
replaced.
DIAGNOSIS AND TESTING
REAR WINDOW DEFOGGER SWITCH
WARNING: On vehicles equipped with airbags, dis-
able the airbag system before attempting any steer-
ing wheel, steering column, or instrument panel
component diagnosis or service. Disconnect 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 disable the air-
bag system. Failure to take the proper precautions
could result in an accidental airbag deployment and
possible personal injury.
NOTE: The rear window defogger switch may be
tested in the vehicle or out of the vehicle, on a
bench.
NOTE: For circuit descriptions and diagrams of the
rear window defogger system, refer to 8W - WIRING
DIAGRAM INFORMATION.
(1) Remove the rear window defogger switch from
the instrument panel, but leave the switch connected
(Refer to 8 - ELECTRICAL/HEATED GLASS/REAR
WINDOW DEFOGGER SWITCH - REMOVAL).
(2) Turn the ignition switch ON.
(3) Using a voltmeter, check for battery voltage at
Pin 3 of the rear window defogger switch (Fig. 6).
(a) If OK, go to Step 4.
(b) If NOT OK, check fuse 7 (15 amp) in fuse
block #1. If fuse is OK, check the wiring circuits.
Refer to 8W - WIRING DIAGRAM INFORMA-
TION.
(4) Check Pin 7, with defogger switch in the On
position there should be battery voltage and, no volt-
age with the switch in the Off position.
(a) If OK, go to Step 5.(b) If NOT OK, no voltage in the On position or
voltage in the Off position, replace the rear window
defogger switch.
(5) Press the defogger switch to the On position.
The indicator lamp should come on and remain on
for approximately 5 minutes.
(a) If OK, install the rear window defogger
switch (Refer to 8 - ELECTRICAL/HEATED
GLASS/REAR WINDOW DEFOGGER SWITCH -
INSTALLATION).
(b) If NOT OK, go to Step 6.
(6) Check Pin 9, with defogger switch in the On
position there should be battery voltage.
(a) If OK, go to Step 7.
(b) If NOT OK, check the wiring circuits. Refer
to 8W - WIRING DIAGRAM INFORMATION.
(7) Check Pin 10 for a good ground.
(a) If OK, replace the rear window defogger
switch.
(b) If NOT OK, check the wiring circuits. Refer
to 8W - WIRING DIAGRAM INFORMATION.
Fig. 6 Rear Window Defogger Switch Connector
VAHEATED GLASS 8G - 5

HEATED MIRRORS
TABLE OF CONTENTS
page page
HEATED MIRRORS
DESCRIPTION..........................9OPERATION............................9
HEATED MIRRORS
DESCRIPTION
The available heated outside rear view mirror sys-
tem is operational anytime the ignition switch is in
the Run position (Fig. 1). When energized, each of
these heater grids produce heat to help clear the out-
side mirrors of ice, snow, or fog.
OPERATION
The electric heater grid located behind the glass of
each of the outside rear view mirrors is energized
when the ignition switch is turned to the Run posi-
tion. The heater grids heat the glass surface of the
outside rear view mirrors.
If the outside mirror heating grids are inoperative,
refer to 8W - WIRING DIAGRAM INFORMATION.
The heating grid behind each outside mirror glass
cannot be repaired and, if faulty or damaged, the
mirror glass must be replaced (Refer to 23 - BODY/
EXTERIOR/MIRROR-SIDE VIEW - GLASS -
REMOVAL).
Fig. 1 SIDE VIEW MIRROR - GLASS
1 - MIRROR GLASS
2 - ELECTRICAL CONNECTORS
3 - GUIDES
VAHEATED MIRRORS 8G - 9

HEATED SEATS
TABLE OF CONTENTS
page page
HEATED SEATS
DESCRIPTION.........................10
OPERATION...........................10
DIAGNOSIS AND TESTING - HEATED SEATS . 11
DRIVER HEATED SEAT SWITCH
DESCRIPTION.........................11
OPERATION...........................11
DIAGNOSIS AND TESTING - DRIVER HEATED
SEAT SWITCH........................11
REMOVAL.............................11
INSTALLATION.........................12
HEATED SEAT ELEMENT
DESCRIPTION.........................12
OPERATION...........................12
DIAGNOSIS AND TESTING - HEATED SEAT
ELEMENT...........................12
HEATED SEAT RELAY
DESCRIPTION.........................12OPERATION...........................13
DIAGNOSIS AND TESTING - HEATED SEAT
RELAY..............................13
REMOVAL.............................13
INSTALLATION.........................13
HEATED SEAT SENSOR
DESCRIPTION.........................13
DIAGNOSIS AND TESTING - HEATED SEAT
SENSOR............................13
PASSENGER HEATED SEAT SWITCH
DESCRIPTION.........................13
OPERATION...........................13
DIAGNOSIS AND TESTING - PASSENGER
HEATED SEAT SWITCH.................14
REMOVAL.............................14
INSTALLATION.........................14
HEATED SEATS
DESCRIPTION
Individually controlled, electrically heated front
seats are available factory-installed optional equip-
ment on this model. Vehicles with this option can be
visually identified by the two separate heated seat
switches mounted in the instrument panel. The
heated seat system allows the front seat driver and
passenger to select from two different levels of sup-
plemental electrical seat heating, or no seat heating
to suit their individual comfort requirements. The
heated seat system for this vehicle includes the fol-
lowing major components, which are described in fur-
ther detail later in this section:
²Heated Seat Elements- Four heated seat ele-
ments are used per vehicle, two for each front seat.
One heating element in the seat back and one in the
seat cushion. The heated seat sensor is integral to
the seat cushion heating element. The heated seat
elements are integral to the front seat and seat back
cushions. Refer to heated seat elements later in this
section for additional information.
²Heated Seat Relay- One heated seat relay is
used per vehicle. The relay is located in the fuse
block and is responsible for distributing the voltage
(B+) to the heated seat elements.
²Heated Seat Sensors- Two heated seat sen-
sors are used per vehicle, one for each front seat. The
heated seat sensors are integral to each of the heatedseat element assemblies. Refer to heated seat sensor
later in this section for additional information.
²Heated Seat Switches- Two heated seat
switches are used per vehicle, one for each front seat.
The switches are mounted in the instrument panel.
Refer to heated seat switches later in this section for
additional information.
Hard wired circuitry connects the heated seat sys-
tem components to each other through the electrical
system of the vehicle. Refer to Wiring for additional
information. The wiring information includes wiring
diagrams, proper wire and connector repair proce-
dures, 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
The heated seat system is designed to provide indi-
vidually controlled, supplemental heat to the seat
cushion and seat back surfaces of both front seats.
Because this system converts electrical current to
heat, the heated seat system can provide a measure
of warm comfort almost immediately upon entering a
cold vehicle, rather than having to wait for the
engine coolant to reach sufficient temperature to
deliver heat through the conventional heater system.
This system allows each front seat occupant to indi-
vidually select one of two comfort levels, Hi or Lo, or
to turn the heater for their seat off.
8G - 10 HEATED SEATSVA

The heated seat system components operate on
battery current received through a fuse in the Fuse
Block on a fused ignition switch output (run-acc) cir-
cuit so that the system will only operate when the
ignition switch is in the On or Accessory positions.
The heated seat system will be turned Off automati-
cally whenever the ignition switch is turned to any
position except On or Accessory. Also, the heated seat
system will not operate when the surface tempera-
ture of the seat cushion cover at either heated seat
sensor is above the designed temperature set points
of the system.DIAGNOSIS AND TESTING - HEATED SEATS
Refer toWiringfor 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.
HEATED SEAT SYSTEM DIAGNOSIS
CONDITION POSSIBLE CAUSES CORRECTION
NO HEATED SEAT SWITCH
ILLUMINATION WITH IGNI-
TION ON1. Faulty fuse. 1. Check heated seat fuse in Fuse Block. Re-
place fuse, if required.
2. Wiring faulty. 2. Check fused ignition switch output (run-acc)
circuit from heated seat switch connector to igni-
tion switch. Repair, if required.
3. Ground faulty. 3. Check for ground at heated seat switch con-
nector. Repair, if required.
4. Faulty switch. 4. Refer to Heated Seat Switch for the proper
switch diagnosis and testing procedures.
DRIVER HEATED SEAT
SWITCH
DESCRIPTION
The heated seat switches are located on the instru-
ment panel, in the accessory switch bezel. The two,
momentary rocker type switches provide a signal to
the Heated Seat Relay through separate hard wired
circuits. Each switch contains two light emitting
diodes (LED), one for each High and Low setting to
let the occupant know that the seat heater system is
on.
The heated seat switches and their LED's cannot
be repaired. If either switch is faulty or damaged the
entire switch must be replaced.
OPERATION
There are three modes that can be selected with
each of the heated seat switches: Off, Low, and High.
When the top of the switch rocker is depressed, the
low mode is selected and the low mode LED indicator
illuminates. Depressing the top of the switch rocker a
second time will turn the heated seat to Off. This
same process is repeated for High heat setting. The
heated seats will automatically return to the Off
mode anytime the vehicle ignition switch is turned
Off.Both switches provide separate hard wire inputs to
the Heated Seat Relay to indicate the selected mode.
The Heated Seat Relay responds to the heated seat
switch messages by controlling the output to the seat
heater elements of the selected seat.
DIAGNOSIS AND TESTING - DRIVER HEATED
SEAT SWITCH
For circuit description and diagrams, refer toWir-
ing.
(1) Inspect the Heated Seat Switches for apparent
damage or sticking/binding and replace if required.
Refer to Heated Seat Switch Removal and Installa-
tion in this section.
(2) Replace the heated seat switch with a known
good unit and retest the heated seat system.
REMOVAL
(1) Disconnect and isolate the negative battery
cable.
(2) Remove the gear selector bezel trim. Refer to
the Body section for the procedure.
(3) Remove the storage bin. Refer to the Body sec-
tion for the procedure.
(4) Remove the switch bezel retaining screw and
remove the switch bezel from the instrument panel.
Refer to the Body section for the procedure.
(5) Disconnect electrical connections.
VAHEATED SEATS 8G - 11

(6) Working from the underside of the switch, gen-
tly rock the switch back and forth out of its mounting
location in the switch bezel.
INSTALLATION
(1) Install the heated seat switch in its mounting
location in the switch bezel.
(2) Connect electrical connections.
(3) Position the switch bezel and install the retain-
ing screw. Refer to the Body section for the proce-
dure.
(4) Install the storage bin. Refer to the Body sec-
tion for the procedure.
(5) Install the gear selector bezel trim. Refer to the
Body section for the procedure.
(6) Connect the negative battery cable.
HEATED SEAT ELEMENT
DESCRIPTION
The heated seat system includes two seat heating
elements in each front seat, one for the seat cushion
(Fig. 1) and the other for the seat back. All models
use two resistor wire heating elements for each seat
that are connected in series with the Heated Seat
Relay. The temperature sensor is a Negative Temper-
ature Coefficient (NTC) thermistor. One temperature
sensor is used for each seat, and it is located in the
seat cushion heating element for all models.The seat heating elements are glued onto the seat
and seat back cushions. The heated seat elements
and the temperature sensor cannot be adjusted or
repaired and, if faulty or damaged a new seat assem-
bly must be installed.
OPERATION
The heated seat elements resist the flow of electri-
cal current. When battery current is passed through
the elements, the energy lost by the resistance of the
elements is released in the form of heat. The heated
seat temperature sensor is a NTC thermistor. When
the temperature of the seat cushion cover rises, the
resistance of the sensor decreases. The heated seat
relay uses this temperature sensor input to monitor
the temperature of the seat, and regulates the cur-
rent flow to the seat heating elements accordingly.
DIAGNOSIS AND TESTING - HEATED SEAT
ELEMENT
For complete circuit diagrams, refer toWiring.
NOTE: When checking heated seat elements for
continuity, be certain to move the heating element
being checked. Moving the element, such as sitting
in the seat will eliminate the possibility of an inter-
mittent open in the element which would only be
evident if the element was in a certain position.
Failure to check the element in various positions
could result in an incomplete test.
(1) Disconnect and isolate the battery negative
cable. Disconnect the heated seat element wire har-
ness connector from under the seat cushion. Check
for continuity between the seat heater driver circuit
and ground. There should be continuity, less than 7
ohms. If OK, go to Step 2. If not OK, replace the seat
assembly.
(2) Check for continuity between the seat heater
B+ driver circuit cavity and the seat back frame.
There should benocontinuity. If OK, heating ele-
ment is OK at this time. If not OK, replace the seat
assembly.
HEATED SEAT RELAY
DESCRIPTION
The heated seat relay is an electromechanical
device that switches 12v battery current to the
heated seat elements when the relay control coil is
energized. The heated seat relay is located in the
Fuse Block, under the drivers seat. The heated seat
relay is a International Standards Organization
(ISO) relay. Relays conforming to the ISO specifica-
tions have common physical dimensions, current
capacities, terminal patterns, and terminal functions.
Fig. 1 Heated Seat Element - Typical
1 - Seat Back Wire Harness
2 - Heated Seat Wire Harness Connector
3 - Heated Seat Cushion Element
8G - 12 HEATED SEATSVA

The heated seat relay cannot be repaired or
adjusted and, if faulty or damaged, it must be
replaced.
OPERATION
The ISO relay consists of an electromagnetic coil, a
resistor or diode, and three (two fixed and one mov-
able) electrical contacts. The movable (common feed)
relay contact is held against one of the fixed contacts
(normally closed) by spring pressure. When the elec-
tromagnetic coil is energized, it draws the movable
contact away from the normally closed fixed contact,
and holds it against the other (normally open) fixed
contact. When the electromagnetic coil is de-ener-
gized, spring pressure returns the movable contact to
the normally closed position. The resistor or diode is
connected in parallel with the electromagnetic coil in
the relay, and helps to dissipate voltage spikes that
are produced when the coil is de-energized.
DIAGNOSIS AND TESTING - HEATED SEAT
RELAY
The heated seat relay is located in the Fuse Block,
under the drivers seat. Refer toWiringfor the loca-
tion of complete heated seat system wiring diagrams.
(1) Remove the heated seat relay from the fuse
block.
(2) A relay in the de-energized position should
have continuity between terminals 87A and 30, and
no continuity between terminals 87 and 30. If OK, go
to Step 3. If not OK, replace the faulty relay.
(3) Resistance between terminals 85 and 86 (elec-
tromagnet) should be 75   5 ohms. If OK, go to Step
4. If not OK, replace the faulty relay.
(4) Connect a battery to terminals 85 and 86.
There should now be continuity between terminals
30 and 87, and no continuity between terminals 87A
and 30. If OK, check the relay supply circuits. If not
OK, replace the faulty relay.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) The heated seat relay is located in the fuse
block, under the drivers seat. Refer to wiring for
detailed location.
(3) Grasp the heated seat relay firmly and pull it
straight out from the fuse block. A slight rocking
motion will aid in removal.
INSTALLATION
(1) Grasp the heated seat relay firmly and push it
straight in the fuse block.
(2) Reconnect the battery negative cable.
HEATED SEAT SENSOR
DESCRIPTION
The heated seat temperature sensor is a Negative
Temperature Coefficient (NTC) thermistor. One tem-
perature sensor is used for each seat. The sensor is
located in the seat cushion heating element for all
models.
The heated seat sensor cannot be adjusted or
repaired and if it is found to be faulty, the complete
heated seat element must be replaced.
DIAGNOSIS AND TESTING - HEATED SEAT
SENSOR
For complete circuit diagrams, refer toWiring.
NOTE: Any resistance values (ohmsV) given in the
following text are supplied using the automatic
range generated by a FLUKETautomotive meter. If
another type of measuring device is used the val-
ues generated may not be the same as the results
shown here, or may have to be converted to the
range used here.
(1) Backprobe the heated seat relay wire harness
connector, do not disconnect. Using an voltmeter,
check the voltage of the seat temperature sensor
input cavity of the heated seat relay wire harness
connector. The seat sensor input voltage should be
between 1.7 volts and 3.0 volts with the system ON.
If OK, sensor is OK at this time. If not OK, replace
the faulty seat cushion heating element and sensor
assembly.
PASSENGER HEATED SEAT
SWITCH
DESCRIPTION
The heated seat switches are located on the instru-
ment panel, in the accessory switch bezel. The two,
momentary rocker type switches provide a signal to
the Heated Seat Relay through separate hard wired
circuits. Each switch contains two light emitting
diodes (LED), one for each High and Low setting to
let the occupant know that the seat heater system is
on.
The heated seat switches and their LED's cannot
be repaired. If either switch is faulty or damaged the
entire switch must be replaced.
OPERATION
There are three modes that can be selected with
each of the heated seat switches: Off, Low, and High.
When the top of the switch rocker is depressed, the
low mode is selected and the low mode LED indicator
illuminates. Depressing the top of the switch rocker a
VAHEATED SEATS 8G - 13