Lexus 2003 LS Owner's Manual page 205

If manual switching of air intake is desired –
21L156

Without rear air conditioning and air purifier
21L060a

With rear air conditioning and air purifier
Each time you push the air intake control button, the mode
changes in order from the RECIRCULATED AIR mode to
AUTOMATIC mode to OUTSIDE AIR mode, then back to the
RECIRCULATED AIR mode. Each indicator light shows which
mode is now selected.
1 RECIRCULATED mode – If quick circulation of cooled air
is desired, select this mode.
2 EXHAUST GAS AUTOMATIC mode – If the outside air
contains harmful substances like exhaust gas (i.e., when
the vehicle running just in front of your vehicle accelerates
rapidly), the system changes automatically from the
OUTSIDE AIR mode (with indicators 2 and 3 on) to
the RECIRCULATED mode (with indicators 1 and 2
on). If you use the EXHAUST GAS AUTOMATIC mode
and the air purifier automatic mode at the same time, air
purifying effect will be enhanced (If equipped).
3
OUTSIDE AIR mode – The system will take fresh outside
air into the vehicle.
Turning off the air conditioning manually will cancel the
EXHAUST GAS AUTOMATIC mode. If you select the "AUTO"
mode during fan operating, the air conditioning turns on and
the EXHAUST GAS AUTOMATIC mode will operate.
For normal use, it is best to keep the air intake control button
set to OUTSIDE AIR mode. If recirculated air is used during
heating, the windows will fog up more easily.
To change the sensitivity of the sensor switching between
the RECIRCULATED and OUTSIDE AIR in the AUTOMATIC
mode, push the air intake control button until you hear a
beep. The display changes as illustrated below.
AIR CONDITIONING
191