Depress the button on the seat belt buckle.
If the belt does not fully retract, pull it out and check for kinks or twists. Then make sure it remains untwisted as it retracts.

NOTE If a belt does not fully retract, inspect it for kinks and twists. If it is still not retracting properly, have it inspected at an Authorized Mazda Dealer.
Fastening the Seat Belt
Front Shoulder Belt AdjusterFront Door Latch And Lock Actuator Inspection
1. The following actuators and switches are integrated with the front door latch
and lock actuator. Inspect the front door latch and lock actuator according to each
inspection procedure for the following items.
Front door lock actuator.
Door lock-link switch.
Door latch s ...
Sunlight/Temperature Sensor
The climate control system measures
inside and outside temperatures, and
sunlight. It then sets temperatures inside
the passenger compartment accordingly.
CAUTION
Do not obstruct either sensor,
otherwise the climate control system
will not operate properly.
...
Parameter Setting Procedure When Tire Size Is Changed
CAUTION:
If the wheel and tire sizes are changed, a discrepancy with the speedometer
needle whereby it exceeds the allowable range could result in a malfunction.
If the wheel and tire sizes are changed, perform the following procedure to
change the tire size parameter setting.
...