Jeep 2009 Grand Cherokee, Owner'S Manual, Page: 274 / 521

When using the air conditioner in extremely heavy
traffic, in hot weather, especially when towing a trailer,
additional engine cooling may be required. If this situa-
tion 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 NEUTRAL and depress the accelerator slightly
for fast idle operation to increase coolant flow and fan
speed.
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
obstructions.
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 ensure adequate
system lubrication to minimize the possibility of com-
pressor damage when the system is started again.
272 UNDERSTANDING YOUR INSTRUMENT PANEL