2003 TOYOTA SIENNA cooling

03 SIENNA_U (L/O 0207)
1372003 MY SIENNA (OM45410U)
The gauge indicates the engine coolant
temperature when the ignition switch is
on. The engine operating temperature
will vary with changes in weather and
engine load.
If the needle moves into the red zone,
your engine is too hot. If your vehicle
overheats, stop your vehicle and allow the
engine to cool.
Your vehicle may overheat during severe
operating conditions, such as:
Driving up a long hill on a hot day.
Reducing speed or stopping after high
speed driving.
Idling for a long period with the air
conditioning on in stopandgo traffic.
Towing a trailer.
NOTICE
Do not remove the thermostat in
the engine cooling system as this
may cause the engine to overheat.
The thermostat is designed to con-
trol the flow of coolant to keep the
temperature of the engine within
the specified operating range.
 Do not continue driving with an
overheated engine. See “If your ve-
hicle overheats” in Section 4.
The tachometer indicates engine speed
in thousands of rpm (revolutions per
minute). Use it while driving to select
correct shift points and to prevent en-
gine lugging and overrevving.
Driving with the engine running too fast
causes excessive engine wear and poor
fuel economy. Remember, in most cases
the slower the engine speed, the greater
the fuel economy.
NOTICE
Do not let the indicator needle get
into the red zone. This may cause
severe engine damage.
Tachometer

03 SIENNA_U (L/O 0207)
1892003 MY SIENNA (OM45410U)
Fan speed selector
Turn the knob to adjust the fan speed—to
the right to increase, to the left to de-
crease.
Temperature selector
Turn the knob to adjust the temperature—
to the right to warm, to the left to cool.
Air flow selector
Turn the knob to select the vents used for
air flow.1. Panel— Air flows mainly from the
instrument panel vents.
2. Bilevel— Air flows from both the floor
vents and the instrument panel vents.
3. Floor— Air flows mainly from the floor
vents.
4. Floor/Windshield— Air flows mainly
from the floor vents and windshield
vents.
Turning the air flow selector to the
floor/windshield position turn on the de-
fogging function with the purpose of
clearing the front view. This position allows the air intake to
select FRESH automatically. This is to
clean up the front view more quickly.
If you want to return the setting to
RECIRCULATE mode, press the air in-
take selector button once again.
Press the “A/C” button for dehumidified
heating or cooling. This setting clears
the front view more quickly.
5. Windshield— Air flows mainly from the
windshield vents.
Turning the air flow selector to the
windshield position turns on the defog-
ging function with the purpose of clear-
ing the front view.
This position allows the air intake to
select FRESH automatically. This is to
clean up the front view more quickly.
If you want to return the setting to
RECIRCULATE mode, press the air in-
take selector button once again.
Press the “A/C” button for dehumidified
heating or cooling. This setting clears
the front view more quickly.
For details about air flow selector settings,
see the illustration after “A/C” button.

03 SIENNA_U (L/O 0207)
1922003 MY SIENNA (OM45410U)
If following another vehicle on a dusty
road, or driving in windy and dusty
conditions, it is recommended that the
air intake selector be temporarily set to
RECIRCULATE, which will close off the
outside passage and prevent outside
air and dust from entering the vehicle
interior.
Heating
For best results, set controls to:
Fan speed— Any setting except “OFF”
Temperature— To w a r d s WARM
(red zone)
Air intake—FRESH (outside air)
Air flow—FLOOR
Air conditioning—OFF
For quick heating, select recirculated
air for a few minutes. To keep the
windows from fogging, select fresh af-
ter the vehicle interior has been
warmed.
Press the “A/C” button on for dehumidi-
fied heating.
Choose floor/windshield air flow to heat
the vehicle interior while defrosting or
defogging the windshield. Air conditioning
For best results, set controls to:
Fan speed— Any setting except “OFF”
Temperature— To w a r d s COLD
(blue zone)
Air intake—FRESH (outside air)
Air flow—PANEL
Air conditioning—ON
For quick cooling, select recirculate air
for a few minutes.
Ventilation
For best results, set controls to:
Fan speed— Any setting except “OFF”
Temperature— To w a r d s COLD
(blue zone)
Air intake—FRESH (outside air)
Air flow—PANEL
Air conditioning—OFF
Defogging
The inside of the windshield
For best results, set controls to:
Fan speed— Any setting except “OFF”
Temperature— To w a r d s WARM
(red zone) to heat;
COLD (blue zone) to
cool
Air intake—FRESH (outside air)
Air flow—WINDSHIELD
Turning the air flow selector to the wind-
shield or floor/windshield position turns on
the defogging function with the purpose of
clearing the front view.
When turning the air flow selector to wind-
shield or floor/windshield position, the air
intake selects FRESH automatically. This
is to clean up the front view more quickly.
If you want to return the setting to
RECIRCULATE mode, press the air intake
selector button once again.
Press the “A/C” button for dehumidified
heating or cooling. This setting clears the
front view more quickly.
On humid days, do not blow cold air
on the windshield—the difference be-
tween the outside and inside tempera-
tures could make the fogging worse.

03 SIENNA_U (L/O 0207)
1932003 MY SIENNA (OM45410U)
Defrosting
The outside of the windshield
For best results, set controls to:Fan speed— Any setting except “OFF”
Temperature— To w a r d s WARM
(red zone)
Air intake—FRESH (outside air)
Air flow—WINDSHIELD
Turning the air flow selector to the wind-
shield or floor/windshield position turns on
the defrosting function with the purpose of
clearing the front view.
When turning the air flow selector to wind-
shield or floor/windshield position, the air
intake selects FRESH automatically. This
is to clean up the front view more quickly.
If you want to return the setting to
RECIRCULATE mode, press the air intake
selector button once again.
Press the “A/C” button for dehumidified
heating or cooling. This setting clears the
front view more quickly.
To heat the vehicle interior while de-
frosting the windshield, choose
floor/windshield air flow.

03 SIENNA_U (L/O 0207)
1952003 MY SIENNA (OM45410U)
“AUTO” button
For automatic operation of the air condi-
tioning, press the “AUTO” button. An indi-
cator light will illuminate to show that the
automatic operation mode has been se-
lected.
In the automatic operation mode, the air
conditioning selects the most suitable fan
speed, air flow, air intake and onoff of
the air conditioning according to the tem-
perature.
When you adjust the temperature selector
button to maximum cooling, a “MAX
COLD” message will appear on the display
and the air intake mode will be automati-
cally changed to RECIRCULATE.
You may use manual controls if you want
to select your own settings.
To turn off the automatic operation, press
the “OFF” button.
Fan speed selector
Push the “
” (increase) or “” (de-
crease) side of the button to adjust the
fan speed.
In automatic operation, you do not have
to adjust the fan speed unless you desire
another fan speed mode. Temperature selector
To increase the temperature, press the
“
” side, to decrease it, press the “”
side.
“MAX COLD” appears when you adjust to
maximum cooling, and “MAX HOT” when
you adjust to maximum warming.
“OFF” button
Push the button to turn off the air condi-
tioning system.
“MODE” button (air flow selector)
Push the “MODE” button to select the
vents used for air flow.
In automatic operation, you do not have
to select the air flow unless you desire
another air flow mode.
1. Panel— Air flows mainly from the
instrument panel vents.
2. Bilevel— Air flows from both the floor
vents and the instrument panel vents.
3. Floor— Air flows mainly from the floor
vents.
4. Floor/Windshield— Air flows mainly
from the floor vents and windshield
vents.

03 SIENNA_U (L/O 0207)
1962003 MY SIENNA (OM45410U)
Windshield air flow button
When this button is pressed, air flows
mainly from the windshield vents and
turns on the defogging function with the
purpose of clearing the front view.
Pressing this button once again returns
the air flow mode to the last one used.
This button allows the air intake to select
FRESH automatically. This is to clean up
the front view more quickly. If you want
to return the setting to RECIRCULATE
mode, press the air intake selector button
once again.
Press the “A/C” button for dehumidified
heating or cooling. This setting clears the
front view more quickly.When the “A/C” button is not pressed in,
pressing another air flow button turns off
the air conditioning.
For details about air flow selector settings,
see the illustration after “A/C” button.
Air intake selector
The air intake selector button is used to
switch the air intake FRESH
mode that
draws outside air into the system and RE-
CIRCULATE mode that recirculates the air
inside vehicle.
To turn the air source to RECIRCULATE
mode, press the button. The indicator will
come on. To turn the air source to FRESH
mode, press the button again. The indica-
tor will go off.
To prevent fogging up of the windshield,
the air intake mode may change automati-
cally to FRESH depending on the condi-
tion of the air conditioning system.
“A/C” button
To turn on the air conditioning, press the
“A/C” button. The “A/C” button indicator
will come on. To turn the air conditioning
off, press the button again.
If the “A/C” button indicator flashes, there
is a problem in the air conditioning system
and the air conditioning automatically
shuts off. If this happens, take your ve-
hicle to a Toyota dealer for service.

03 SIENNA_U (L/O 0207)
1982003 MY SIENNA (OM45410U)
If following another vehicle on a dusty
road, or driving in windy and dusty
conditions, it is recommended that the
air intake selector be temporarily set to
RECIRCULATE, which will close off the
outside passage and prevent outside
air and dust from entering the vehicle
interior.
Heating
For best results, set controls to:
For automatic operation—
Press in the “AUTO” button.
Temperature— To the desired
temperature
Air intake—FRESH (outside air)
Air conditioning—OFF
For manual operation—
Fan speed— To the desired fan speed
Temperature— Towards high temperature
Air intake—FRESH (outside air)
Air flow—FLOOR
Air conditioning—OFF
For quick heating, select recirculated
air for a few minutes. To keep the
windows from fogging, select fresh af-
ter the vehicle interior has been
warmed.
Press the “A/C” button on for dehumidi-
fied heating.
Choose floor/windshield air flow to heat
the vehicle interior while defrosting or
defogging the windshield.
Air conditioning
For best results, set controls to:
For automatic operation—
Press in the “AUTO” button.
Temperature— To the desired
temperature
Air intake—FRESH (outside air)
Air conditioning—ON
For manual operation—
Fan speed— To the desired fan speed
Temperature— Towards low temperature
Air intake—FRESH (outside air)
Air flow—PANEL
Air conditioning—ON
For quick cooling, select recirculated
air for a few minutes.
Ventilation
For best results, set controls to:
For automatic operation—
Press in the “AUTO” button.
Temperature— To w a r d s low temperature
Air intake—FRESH (outside air)
Air conditioning—OFF
For manual operation—
Fan speed— To the desired fan speed
Temperature— To w a r d s low temperature
Air intake—FRESH (outside air)
Air flow—PANEL
Air conditioning—OFF

03 SIENNA_U (L/O 0207)
1992003 MY SIENNA (OM45410U)
Defogging
The inside of the windshield
For best results, set controls to:
For automatic operation—Temperature— To w a r d s high temperature
to heat; low temperature
to cool
Air intake—FRESH (outside air)
Air flow—WINDSHIELD
For manual operation—
Fan speed— To the desired fan speed
Temperature— To w a r d s high temperature
to heat; low temperature
to cool
Air intake—FRESH (outside air)
Air flow—WINDSHIELD
If your windshield is fogging, turn on the
defogger by pushing the “MODE” button to
select the floor/windshield vent, or push
the windshield air flow button.
The defogger is not automatically set to
either floor/ windshield or windshield air
flow.
If the windshield is fogging, manually turn
on the defogger. When pressing the windshield air flow but-
ton, the air intake selects FRESH auto-
matically. This is to clean up the front
view more quickly.
If you want to return the setting to
RECIRCULATE mode, press the air intake
selector button once again.
Press the “A/C” button for dehumidified
heating or cooling. This setting clears the
front view more quickly.
On humid days, do not blow cold air
on the windshield—the difference be-
tween the outside and inside tempera-
tures could make the fogging worse.
Defrosting
The outside of the windshield
For best results, set controls to:
For automatic operation—
Temperature— To w a r d s high temperature
Air intake—FRESH (outside air)
Air flow—WINDSHIELD
For manual operation—
Fan speed— To the desired fan speed
Temperature— To w a r d s high temperature
Air intake—FRESH (outside air)
Air flow—WINDSHIELD
If your windshield is frosting, turn on the
defroster by pushing the “MODE” button to
select the floor/windshield vent, or push
the windshield air flow button.
The defroster is not automatically set to
either floor/windshield or windshield air
flow.
If the windshield is frosting, manually turn
on the defroster.
When pressing the windshield air flow but-
ton, the air intake selects FRESH auto-
matically. This is to clean up the front
view more quickly.
If you want to return the setting to
RECIRCULATE mode, press the air intake
selector button once again.
Press the “A/C” button for dehumidified
heating or cooling. This setting clears the
front view more quickly.
To heat the vehicle interior while de-
frosting the windshield, choose
floor/windshield air flow.