Ford Automobile Owner's Manual page 235

Driving
While receiving a warning the radio volume will be reduced to a
predetermined level. After the warning goes away, the radio will return
to the previous value.
The RSS automatically turns on when the gearshift lever is placed in R
(Reverse) and the ignition is on. A control in the message center allows
the driver to disable the system, refer to Message center in the Driver
Controls chapter for more information.
Keep the RSS sensors (located on the rear bumper/fascia) free
from snow, ice and large accumulations of dirt (do not clean the
sensors with sharp objects). If the sensors are covered, it will
affect the accuracy of the RSS.
If your vehicle sustains damage to the rear bumper/fascia, leaving
it misaligned or bent, the sensing zone may be altered causing
inaccurate measurement of obstacles or false alarms.
BLIND SPOT MIRRORS (IF EQUIPPED)
Blind spot mirrors have an
integrated convex spotter mirror
built into the upper outboard corner
of the outside mirrors. They are
designed to assist the driver by
increasing visibility along the side of
the vehicle. For more information on
your side view mirrors, refer to
Exterior Mirrors in the Driver
Controls chapter.
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