Lexus 2004 GX470 Owner's Manual page 244

(e) Checking and replacing the air conditioning
filter
The air conditioning filter information label is placed in the
glove box as shown and indicates that a filter has been
installed.
The air conditioning filter prevents dust from entering the
vehicle through the air conditioning vent.
The air conditioning filter is behind the glove box.
The air conditioning filter may clog after long use. The filter
may need to be replaced if the air flow of the air conditioner and
heater experiences extreme reductions in operating efficiency,
or if the windows begin to fog up easily.
To maintain the air conditioning efficiency, inspect and replace
the air conditioning filter according to the maintenance
schedule. In dusty areas or areas with heavy traffic flow, such
as inner city or desert areas, early replacement may be
required. (For scheduled maintenance information, please
refer to the "Owner's Manual Supplement/Scheduled
Maintenance".)
AIR CONDITIONING
229