Checking the function

HINT: The wiper blades make a reference stroke to determine the cleanliness and condition of the windshield when the rain sensor is activated. The rain sensor is deactivated when the ignition is switched off. To reactivate the rain sensor with the ignition on, move the stalk to position "0" and then to intermittent wiping. 

Spray water on the windshield where the rain sensor is positioned.

The wiper blades must now wipe the windshield clean.

HINT: In cars equipped with the rain sensor it replaces the intermittent function. One way of checking the function of the rain sensor is to twist the collar on the lever. This changes the sensitivity of the rain sensor. The windshield wiper should make one stroke. If the intermittent or high speed functions are activated it indicates that the rain sensor function is missing. 

Refer to Checking the supply to the rain sensor