Fiat 500X 2017 Owner's Manual page 170

168 SAFETY
Inserting Latch Plate Into Buckle
3. When the seat belt is long enough to fit, insert the
latch plate into the buckle until you hear a "click."
Positioning The Lap Belt
4. Position the lap belt so that it is snug and lies low
across your hips, below your abdomen. To remove
slack in the lap belt portion, pull up on the shoulder
belt. To loosen the lap belt if it is too tight, tilt the
latch plate and pull on the lap belt. A snug seat belt
reduces the risk of sliding under the seat belt in a
collision.