Ford Focus Owner's Manual page 76

Instrument Cluster
Door open
A warning chime will sound when any door
is opened if the vehicle exceeds a relatively
low speed.
Lights on
A warning chime will sound if the driver's
door is opened with the exterior lights
switched on and the ignition switched off.
Low fuel
A warning chime will sound when the
remaining fuel is less than approximately
6 litres (1.3 gallons).
Seat belt reminder
See Seat belt reminder (page 26).
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