Ford 1998 Windstar Owner's Manual page 96

Speed Dependent Wipers
This feature compensates for the extra moisture that
accumulates on your windshield at higher speeds during rain.
At higher speeds, the Speed Dependent feature shortens the
delay between wipes when you use the variable interval wipers.
Delay will automatically adjust at speeds between 10 and
65 mph (16 and 105 km/h).
The Speed Dependent feature comes disabled from the factory,
but can be activated at any time by using the following
procedure.
Make sure the two front doors are securely closed.
1.
Insert the key into the ignition and turn first to the ON
2.
position (the gauges on the instrument panel will not
illuminate) and then back to the OFF position. Remove the
key and within 30 seconds, perform the following sequence:
Press and hold the washer button on the end of the turn
3.
signal lever.
Within two seconds, put the key back in the ignition and
4.
turn to the ON position.
Hold the washer button down until a long (two second) tone
5.
is heard. Release the button while the tone is active.
After the long tone, a confirmation sequence will be heard.
6.
One beep indicates the feature is inactive. Two beeps
indicates the feature is active.
Repeat this procedure any time you want to cancel or reactivate
the Speed Dependent feature.
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