Chevrolet 1993 Astro Passenger Owner's Manual page 90

Features & Controls
K3387
You control your rear window wipedwasher from a switch on your instrument
panel, just left
of
your steering column.
Press the top of the switch to the first position to turn on the wiper.
Press the top
of the switch in
all the way and hold to release the
desired amount of washer fluid. The wipers will continue to work after
you release the switch.
Press the bottom of the switch (OFF) to turn the wiper off,
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