FORD 2004 F-150 v.1 - Manual (Page 110)

Conditions of operation
If... Then...
The driver’s safety belt is not
buckled before the ignition
switch is turned to the ON
position... The safety belt warning light
illuminates 1-2 minutes and the
warning chime sounds 4-8 seconds.
The driver’s safety belt is
buckled while the indicator
light is illuminated and the
warning chime is sounding... The safety belt warning light and
warning chime turn off.
The driver’s safety belt is
buckled before the ignition
switch is turned to the ON
position... The safety belt warning light and
indicator chime remain off.
BeltMinder
Your vehicle will either have a BeltMinder feature which functions only
for the driver’s seating position (driver-only BeltMinder) or a BeltMinder
feature which functions for both the driver and passenger seating
positions (driver/passenger BeltMinder).
Driver-only BeltMinder (if equipped)
The BeltMinder feature is a supplemental warning to the safety belt
warning function. This feature provides additional reminders to the
driver that the driver’s safety belt is unbuckled by intermittently
sounding a chime and illuminating the safety belt warning lamp in the
instrument cluster.
Seating and Safety Restraints
110