Ford 2004 Windstar Owner's Manual page 175

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.
Certain add-on devices such as large trailer hitches, bike or
surfboard racks and any device that may block the normal
detection zone of the RSS system may create false beeps.
The RSS detects obstacles up to 2
meters (6 ft.) from 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
obstacle is less than 25.0 cm (10
in.) away, the tone will sound
continuously. If the RSS 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 RSS is automatically enabled
when the gear selector is placed in
R (Reverse) and the ignition is ON.
The park aid disable switch allows
the driver to disable the RSS only
when the ignition is ON, and the
gear selector is in R (Reverse). The
2004 Windstar (win)
Owners Guide (post-2002-fmt)
USA English (fus)
Driving
OFF
175