Opel 2015 Astra Owner's Manual page 106

104 Instruments and controls
Adjustable sensitivity of the rain
sensor
Turn the adjuster wheel to adjust the
sensitivity:
low sensitivity = turn adjuster
wheel downwards
high sensitivity = turn adjuster
wheel upwards
Keep the sensor free from dust, dirt
and ice.
Windscreen and headlight
washer
Pull lever. Washer fluid is sprayed
onto the windscreen and the wiper
wipes a few times.
If the headlights are on, washer fluid
is also sprayed onto the headlights,
provided that the lever is pulled
sufficiently long. Afterwards, the
headlight washer system is
inoperable for 5 wash cycles or until
engine or headlights have been
switched off and on again.