Lexus 2004 GX470 Owner's Manual page 49

SWITCHES
NOTICE
Do not operate the wipers if the windshield is dry. It may
scratch the glass.
Raindrop detection type
"
1 Automatic control adjuster
2 Washer on
34
To turn the wipers on, move the lever down until you reach
the desired speed setting.
The ignition switch must be in the "ON" position.
There are 3 settings:
"AUTO" position: Automatic operation
"LO" position: Low speed operation
"HI" position: High speed operation
Automatic operation
The wiper speed is determined by the amount of raindrops
and sunlight detected by the automatic wiper control
sensor.