Turn the auxiliary key toward the front to lock, toward the back to unlock.
To lock
All doors lock automatically when the driver's door is locked using the auxiliary key.
To unlock
The driver’s door unlocks when the auxiliary key is turned briefly to the unlock position and then immediately returned to the center position.
All doors unlock when the driver's door is unlocked and the auxiliary key is held in the unlock position for one second or longer.

Door Locks
Locking, Unlocking with Request Switch, Door Handle (With the advanced keyless
function)Mazda 6 Owners Manual: Seat Belt Maintenance
1. Clean the soiled area by lightly dabbing it with a soft cloth soaked in a
mild detergent (approx. 5%) diluted with water.
2. Wipe off the remaining detergent using a cloth soaked in clean water and wrung
out well.
3. Before retracting seat belts which have been pulled out for cleaning, dry ...
Mazda 6 Owners Manual: No.9 noise while operating a/c system
Diagnostic procedure
* : If there is gas leakage, air enters into the A/C system. The desiccant
within the receiver/drier absorbs the moisture from the air and becomes
saturated. If the A/C system is used in this condition, the inside of the A/C
compressor will begin to rust due to this ...