2007 Jeep Grand Cherokee Owner's Manual - Page 242

242 UNDERSTANDING YOUR INSTRUMENT PANEL 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 hamper 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. 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 (cigarette smoke, 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.