Toyota Sienna 2010 Owner's Manual page 86

Release method
■
The belt can be completely released when not required, such as
when folding down the third seat.
STEP 1
STEP 2
Extracting the belt
■
1-3. Adjustable components (seats, mirrors, steering wheel)
Insert the key into the hole on
the center seat belt buckle to
release the tab (with the hooked
end), and allow the belt to
retract.
Stow the seat belt tabs in the
cover set in the roof as shown.
Pull tab out and pull the belt
out a little. Then pull tab
1
out.
87