Lexus 2003 LS Owner's Manual page 54

SWITCHES
Replacing the air filters
The air filters may clog after the long use of the climate control
seats which will reduce the air flow. However, you can inspect
the filters easily.
When you replace the air filters, be sure to turn off the fans.
12L130
1 Remove the air filter locks.
2 Remove the air filter.
The climate control seat filters are located under the driver and
front passenger seats.
Replace the air filter when the performance of air flow becomes
low by the deterioration of filter.
40
NOTICE
The air filter should be installed properly in position.
The use of climate control seat with the air filter
removed may cause the malfunction of the climate
control seat.