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 AdjusterMazda 6 Owners Manual: Rear side seat belt removal/installation
Caution
The ELR has a spring that will unwind if the retractor's cover is
removed. The spring cannot be rewound by hand. If this occurs, the ELR will
not work properly. Therefore, do not disassemble the retractor.
4SD
1. Fold the rear seat back.
2. Remove the rear side seats.
3. Remo ...
Mazda 6 Owners Manual: Supplemental Restraint System (SRS) Precautions
The front and side supplemental restraint systems (SRS) include different types
of air bags. Please verify the different types of air bags which are equipped
on your vehicle by locating the “SRS AIRBAG” location indicators. These indicators
are visible in the area where the air bags are in ...