Ford 2001 Windstar Owner's Manual page 79

This system is not designed to prevent contact with small or
moving objects. The system is designed to provide a warning to
assist the driver in detecting large stationary objects to avoid damaging
the vehicle. The system may not detect smaller objects, particularly
those close to the ground.
The RSS will assist the driver in detecting certain objects while the
vehicle slowly moves in reverse at speeds less than 6 km/h (4 mph). The
RSS is not effective at speeds greater than 6 km/h (4 mph) and may not
detect certain angular or moving objects.
The reverse sensing system detects
obstacles within approximately 1.8
meters (5.9 ft.) of the rear bumper
with a decreased coverage area at
the outer corners of the bumper,
(refer to the figures for approximate
zone coverage areas). As you move
closer to the obstacle, the rate of
the tone increases. When the
distance to the obstacle is less than
25.0 cm (10 in.), the tone will sound
continuously. If the system detects a
stationary or receding object further
than 25.0 cm (10 in.) from the side
of the vehicle, the tone will sound
for only three seconds. Once the
system detects an object
approaching, the tone will sound
again.
The reverse sensing system is
automatically enabled when the gear
selector is placed in R (Reverse)
and the ignition is ON. A reverse
sensing control allows the driver to
disable the reverse sensing system
only when the ignition is ON, and
the gear selector is in R (Reverse).
Controls and features
OFF
79