Lexus 2004 LS430 Owner's Manual page 81

With the ignition switch turned off, if the windshield sensor is
touched by reason of cleaning the windshield or for any other
reason, either of the following operations may cause automatic
wiper activation.
D Turning the ignition switch on with the wiper lever in the
"AUTO" position.
D Turning the ignition switch on and move the wiper lever
down in the "AUTO" position.
Even with the wiper lever in the "AUTO" position, the system
will switch to intermittent operations if the system malfunctions.
The system will turn off if the windshield gets extremely hot (at
more than 80_C or 176_F) or cold (at less than –10_C or 14_F).
When the ignition switch is turned off with the wiper lever in the
"AUTO" position, and then the ignition switch is turned on
again, the automatic operation may not work even if raindrops
are on the windshield.
In this case, move the lever to another position and return it to
the "AUTO" position again.
CAUTION
Be careful not to get your fingers caught between the
wipers and windshield.
When the wiper lever is in the "AUTO" position with the
ignition switch on, the wipers
automatically in the following cases:
D If you touch the upper center of the windshield
adjacent to the sensor.
D If you wipe the upper center of the windshield
(adjacent to which the sensor is located) with a towel.
D If the windshield vibrates.
D If you touch the sensor.
SWITCHES
could operate
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