2008 JEEP GRAND CHEROKEE Owners Manual

UNDERSTANDING YOUR INSTRUMENT PANEL 265
4

NOTE:Regardless of the type of operation, when a
temperature knob is set to the full clockwise or full
counterclockwise position, the system will deliver full
hot or full cold air out of the ducts, respectively.
The operator can override the AUTO mode setting and
select the direction of the air by rotating the right mode
knob to one of the following positions. When the Mode is
set to any position other than AUTO, the automatic
control of air temperature is disabled. The user must
adjust the temperature knobs to obtain the desired tem-
perature.
²Defrost
Air is directed to the windshield through the
outlets at the base of the windshield. Air is also
directed to the front door windows through the side
window demister grilles. Some airflow is delivered to
the floor while in defrost so that comfort can be
maintained.NOTE:The defrost mode is not automatically selected.
It must be manually selected, when desired.
²Defrost/Floor
Air flows through the front and rear floor outlets
and the outlets at the base of the windshield. Air
is also directed to the front door windows
through the side window demister grilles. Some air-
flow is delivered to the floor while in defrost so that
comfort can be maintained.
²Floor
Air flows through the floor outlets located under
the instrument panel and into the rear seating
area through vents under the front seats. Some airflow
is delivered to defrost while in floor mode, so that
comfort can be maintained.
²Bi-Level
Air flows both through the outlets located in the
instrument panel and those located on the floor.
266 UNDERSTANDING YOUR INSTRUMENT PANEL

Air flows through the registers in the back of the
center console, and under the front seats to the rear
seat passengers. These registers can be closed to block
airflow. The center console outlets deliver conditioned
air while the floor outlets deliver heated air.
²Panel
Air flows through the outlets located in the in-
strument panel. Air flows through the registers in
the back of the center console to the rear seat passen-
gers. These registers can be closed to block airflow.
Depress this button to turn on and off the air
conditioning during manual operation only. Con-
ditioned outside air is then directed through the
outlets selected on the mode control dial. The button
includes an LED that illuminates when manual operation
is selected.
NOTE:To manually control the air conditioning the
mode selector must be moved out of the AUTO position.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.
NOTE:Extended use of recirculation may cause the
windows to fog. If the interior of the windows begins to
fog, press the ªRecirculateº 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
ªRecirculateº 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.
UNDERSTANDING YOUR INSTRUMENT PANEL 267
4

Operating Tips
Window Fogging
Windows will fog on the inside when the humidity inside
the vehicle is high. This often occurs in mild or cool
temperatures when it's rainy or humid. In most cases
turning on the Air-conditioning (pressing the snowflake
button) will clear the fog. Adjust the temperature control,
air direction and blower speed to maintain comfort.
As the temperature gets colder it may be necessary to
direct air onto the windshield. Adjust the temperature
control and blower speed to maintain comfort. Higher
blower speeds will reduce fogging. Interior fogging on
the windshield can be quickly removed by selecting the
defrost mode.
Regular cleaning of the inside of the windows with a
non-filming cleaning solution (vinegar and water works
very well) will help prevent contaminates (cigarettesmoke, perfumes, etc.) from sticking to the windows.
Contaminates increase the rate of window fogging.Summer Operation
Air conditioned vehicles must be protected with a high
quality antifreeze coolant during summer to provide
proper corrosion protection and to raise the boiling point
of the coolant for protection against overheating. A 50 %
concentration is recommended. Refer to Recommended
Fluids and Genuine Parts for the proper coolant type.
When using the air conditioner in extremely heavy traffic
in hot weather especially when towing a trailer, addi-
tional engine cooling may be required. If this situation is
encountered, operate the transmission in a lower gear to
increase engine RPM, coolant flow and fan speed. When
stopped in heavy traffic, it may be necessary to shift into
N (Neutral) and depress the accelerator slightly for fast
idle operation to increase coolant flow and fan speed.
268 UNDERSTANDING YOUR INSTRUMENT PANEL

Your air conditioning system is also equipped with an
automatic recirculation system. When the system senses
a heavy load or high heat conditions, it may use partial
Recirculation A/C mode to provide additional comfort.
Winter Operation
When operating the system during the winter months,
make sure the air intake, located directly in front of the
windshield, is free of ice, slush, snow, or other obstruc-
tions.
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.
UNDERSTANDING YOUR INSTRUMENT PANEL 269
4

Operating Tips Chart
270 UNDERSTANDING YOUR INSTRUMENT PANEL

STARTING AND OPERATING
CONTENTS
mStarting Procedure......................275
NNormal Starting Ð Gasoline Engines.......276
NExtremely Cold Weather (Below220ÉF Or
229ÉC).............................276
NIf Engine Fails To Start.................277
NAfter Starting........................278
NNormal Starting Ð Diesel Engines.........278
mEngine Block Heater Ð If Equipped.........283
mAutomatic Transmission..................284NShift Lock Manual Override Ð If Equipped . . . 284
NBrake/Transmission Interlock System.......285
N5±Speed Automatic Transmission..........285
NGear Ranges.........................286
NRocking The Vehicle...................292
mFour-Wheel Drive Operation...............293
NQuadra-Trac ItOperating Instructions/
Precautions Ð If Equipped..............293
NQuadra-Trac IItOperating
Instructions/Precautions Ð If Equipped.....293
5

NShift Positions........................295
NShifting Procedures....................296
NQuadra-Drive IItSystem Ð If Equipped.....299
mOn-Road Driving Tips...................299
mOff-Road Driving Tips...................300
NWhen To Use 4WD Low Range Ð
If Equipped.........................300
NDriving Through Water.................300
NDriving In Snow, Mud And Sand..........301
NHill Climbing........................301
NTraction Downhill.....................302
NAfter Driving Off-Road.................303
mParking Brake.........................304mAnti-Lock Brake System..................305
mPower Steering........................308
mMulti Displacement System (MDS) Ð 5.7L Engine
Only................................309
mTire Safety Information...................310
NTire Markings........................310
NTire Identification Number (TIN)..........313
NTire Loading And Tire Pressure...........314
mTires Ð General Information...............318
NTire Pressure.........................318
NTire Inflation Pressures.................319
NTire Pressures For High Speed Operation....321
NRadial-Ply Tires......................321
272 STARTING AND OPERATING