2005 JEEP GRAND CHEROKEE cooling

12. Tire Pressure Monitor Warning Light
This light will turn on continuously when there
is a low tire pressure condition. The light will
also turn on if a problem exists with any tire
sensor. When a system fault is detected, the
indicator lamp will flash repetitively for ten seconds. The
flash cycle will repeat every ten minutes or until the fault
condition is removed and reset. The light will remain on
or flashing until the tire pressure is properly set or the
problem with the sensor is corrected.
This light will turn on momentarily as a bulb check when
the engine is started.
When the tire pressure monitoring system warning light
is lit, one or more of your tires is significantly underin-
flated. You should stop and check your tires as soon as
possible, and inflate them to the proper pressure as
indicated on the tire and loading information placard.
Driving on a significantly underinflated tire causes thetire to overheat and can lead to tire failure. Underinfla-
tion also reduces fuel efficiency and tire tread life, and
may affect the vehicle’s handling and stopping ability.
Each tire, including the spare, should be checked
monthly when cold and set to the recommended inflation
pressure as specified in the tire and loading information
placard. (See page 269 for more information.)
13. Temperature Gauge
The temperature gauge shows engine coolant tempera-
ture. Any reading within the normal range indicates that
the engine cooling system is operating satisfactorily.
The gauge pointer will likely indicate a higher tempera-
ture when driving in hot weather, up mountain grades,
or when towing a trailer. It should not be allowed to
exceed the upper limits of the normal operating range.
UNDERSTANDING YOUR INSTRUMENT PANEL 167
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CAUTION!
Driving with a hot engine cooling system could
damage your vehicle. If temperature gauge reads (H),
pull over and stop the vehicle. Idle the vehicle with
the air conditioner turned off until the pointer drops
back into the normal range. If the pointer remains on
the “H”, and you hear continuous chimes, turn the
engine off immediately, and call for service.
WARNING!
A hot engine cooling system is dangerous. You or
others could be badly burned by steam or boiling
coolant. If you decide to look under the hood your-
self, refer to Section 7 of this manual. Follow the
warnings under “Cooling System Pressure Cap.”
14. Electronic Vehicle Information Center Display
When the appropriate conditions exist, this display
shows the Electronic Vehicle Information Center (EVIC)
messages. Refer to “Electronic Vehicle Information Cen-
ter” later in this section. (See page 171 for more informa-
tion.)
15. TOW/HAUL Indicator Light
This light will illuminate when the TOW/
HAUL button has been selected. The TOW/
HAUL button is located in the center of the
instrument panel (below the climate controls).
16. 4WD LOW Mode Indicator Light — If Equipped
This light alerts the driver that the vehicle is in
the 4WD LOW mode. The front and rear drive-
shafts are mechanically locked together forcing
the front and rear wheels to rotate at the same
speed. (See page 239 for more information.)
168 UNDERSTANDING YOUR INSTRUMENT PANEL

Automatic Temperature Control — If Equipped
The Infrared Dual-Zone Climate Control System auto-
matically maintains the interior comfort level desired by
the driver and passenger. This is accomplished by a dual
sun-sensor in the top of the instrument panel, and an
infrared sensor located in the face of the control unit.
There are also various sensors monitored by this system
which take account for vehicle speed, A/C pressure,
outside temperature, and engine cooling temperature.
The infrared sensor independently measures the surface
temperature of the driver and passenger. Based on the
sensor input, the system automatically adjusts the air
flow temperature, the air flow volume, and amount of
outside air recirculation. This maintains a comfortable
temperature even under changing conditions.Operation of the system is quite simple. Begin by turning
the right mode knob to AUTO, and place the blower
control (left knob) to either LO AUTO or HI AUTO. The
LO AUTO position should be used for front seat occu-
pants only. The HI AUTO position should be used when
more air flow is desired, or when rear seat occupants are
Automatic Temperature Controls
218 UNDERSTANDING YOUR INSTRUMENT PANEL

NOTE:To manually control the air conditioning the
mode selector must be moved out of the AUTO position.
Press this button to turn on the rear window
defroster and the heated side mirrors (if
equipped). An LED in the button will illuminate indicat-
ing that the rear window defroster is ON. The defroster
automatically turns off after approximately 10 minutes of
operation for the first push of the button, and will turn
off after approximately 5 minutes for the second push of
the button.CAUTION!
To avoid damaging the electrical conductors of the
rear window defroster, do not use scrapers, sharp
instruments, or abrasive window cleaners on the
interior surface of the window.
Labels can be peeled off after soaking with warm
water.
This button can be used to block out smoke,
odors, dust, high humidity, or if rapid cooling
is desired. The recirculation mode should only
be used temporarily. The button includes an
LED that illuminates, which indicates that the recircula-
tion mode is active. You may use this feature separately.
UNDERSTANDING YOUR INSTRUMENT PANEL 223
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NOTE:Extended use of recirculation may cause the
windows to fog. If the interior of the windows begins to
fog, press the “Recirculate” icon button to return to
outside air. Some temp./humidity conditions will cause
captured interior air to condense on windows and ham-
per visibility. For this reason, the system will not allow
“Recirculate” to be selected while in the defrost or
defrost/floor modes. Attempting to use the recirculation
while in these modes will cause the LED in the button to
blink and then turn off.
Summer Operation
The engine cooling system in air conditioned vehicles
must be protected with a high-quality antifreeze coolant
to provide proper corrosion protection and to protect
against engine overheating. A 50% solution of ethylene
glycol antifreeze coolant in water is recommended. Refer
to “Maintenance Procedures” in Section 7 of this manual
for proper coolant selection.
Winter Operation
Use of the air Recirculation mode during winter months
is not recommended because it may cause window
fogging.
NOTE:Refer to the “Operating Tips” chart (for Manual
A/C Control) in this section for suggested control set-
tings in different weather conditions.
Vacation Storage
Anytime you store your vehicle, or keep it out of service
(i.e. vacation) for two weeks or more, run the air condi-
tioning system at idle for about five minutes in the fresh
air and high blower setting. This will insure adequate
system lubrication to minimize the possibility of com-
pressor damage when the system is started again.
224 UNDERSTANDING YOUR INSTRUMENT PANEL

▫Tire Pressure Monitoring — Premium System. . 271
▫General Information...................275

Tire Chains...........................275

Tire Rotation Recommendations............276

Fuel Requirements......................277
▫3.7/4.7L Engines (If Equipped)............277
▫5.7L Engines (If Equipped)...............277
▫Reformulated Gasoline.................278
▫Gasoline/Oxygenate Blends..............278
▫MMT In Gasoline.....................279
▫Materials Added To Fuel................279
▫Fuel System Cautions..................279
▫Carbon Monoxide Warnings..............280

Fuel Tank Filler Cap (Gas Cap).............281▫Loose Fuel Filler Cap Message............282

Trailer Towing.........................283
▫Trailer And Tongue Weight..............285
▫Trailer Tow Wiring....................286
▫Cooling System Tips—Trailer Towing.......287
▫Trailer Classifications...................288
▫Trailer Towing Capability................289

Recreational Towing (Behind Motorhome, Etc.) . . 290
▫Towing – 2WD Models.................290
▫Towing — Quadra-Trac I (Single-Speed
Transfer Case) 4WD Models..............290
▫Towing — Quadra–Trac II /Quadra–Drive II
4WD Models........................290

Snow Plow...........................293
STARTING AND OPERATING 229
5

Cooling System Tips—Trailer Towing
To reduce potential for engine and transmission over-
heating in high ambient conditions, take the following
actions:
•City Traffic
When stopped, put transmission in N (Neutral) and
increase engine idle speed.
•Highway Driving
Reduce speed.
•Air Conditioning
Turn off temporarily.
To reduce the potential for transmission overheating,
turn the “TOW/HAUL” feature on when driving in hilly
areas or downshift the transmission to the next lower
gear range to eliminate excessive transmission shifting.
This action will also reduce the possibility of transmis-
sion overheating and provide better engine braking.
7–Pin Connector
STARTING AND OPERATING 287
5

IF YOUR ENGINE OVERHEATS
In any of the following situations, you can reduce the
potential for overheating by taking the appropriate ac-
tion.
•On the highways — Slow down.
•In city traffic — While stopped, put transmission in N
(Neutral), but do not increase engine idle speed.
NOTE:There are steps that you can take to slow down
an impending overheat condition. If your air conditioner
is on, turn it off. The air conditioning system adds heat to
the engine cooling system and turning off the A/C
removes this heat. You can also turn the Temperature
Control to maximum heat, the Mode Control to floor, and
the Fan Control to High. This allows the heater core to act
as a supplement to the radiator and aids in removing heat
from the engine cooling system.
CAUTION!
Driving with a hot cooling system could damage
your vehicle. If the temperature gauge reads “H”,
pull over and stop the vehicle. Idle the vehicle with
the air conditioner turned off until the pointer drops
back into the normal range. If the pointer remains on
the “H”, and you hear continuous chimes, turn the
engine off immediately, and call for service.
WHAT TO DO IN EMERGENCIES 297
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