Jeep Grand Cherokee SRT8 2012 Owner's Manual page 55

2. The seat belt latch plate is above the back of your seat.
Grasp the latch plate and pull out the belt. Slide the latch
plate up the webbing as far as necessary to make the belt
go around your lap.
Latch Plate
THINGS TO KNOW BEFORE STARTING YOUR VEHICLE 53
3. When the belt is long enough to fit, insert the latch
plate into the buckle until you hear a "click."
Latch Plate to Buckle
2