Volvo 2008 V70 Owner's Manual page 87

Rain sensor (option)
The rain sensor automatically regulates wiper speed according to the amount of water on the windshield.The sensitivity
of the rain sensor can be adjusted moving the thumb wheel up (the wipers will sweep the windshield more frequently)
or down (the wipers will sweep the windshield less frequently).
NOTE
The wipers will make an extra sweep each time the thumb wheel is adjusted upward.
When the rain sensor is activated, the symbol
Activating and setting the sensitivity
When activating the rain sensor, the vehicle must be running or in ignition mode II and the windshield wiper lever
must be in position 0 or in the single sweep position.
Activate the rain sensor by pressing the button
Press the lever up for the wipers to make an extra sweep. The rain sensor returns to active mode when the stalk is
released back to position 0.
Deactivating
Deactivate the rain sensor by pressing the button
The rain sensor is automatically deactivated when the key is removed from the ignition
97
03 Your driving environment
Wipers and washers
slot or five minutes after the ignition has been switched off.
CAUTION
The rain sensor should be deactivated when washing the car in an automatic car wash, etc. If the rain sensor function
is left on, the wipers will start inadvertently in the car wash and could be damaged.
Windshield washing
will illuminate in the instrument panel.
. The windshield wipers will make one sweep.
or press the lever down to another wiper position.