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: Panel light control switch removal/installation
1. Disconnect the negative battery cable.
2. Remove in the order indicated in the table.
3. Install in the reverse order of removal.
Panel Light Control Switch Removal Note
1. Insert your hand from the lower side of the dashboard and squeeze the tabs
of the panel light control switch.
2. ...
Mazda 6 Owners Manual: Windshield installation
Caution
To prevent the sealant from cracking or the glass from being
pushed out by air pressure if a door is closed, open all of the windows and
leave them open until the sealant has hardened.
1. Cut away the old sealant using a razor so that 1-2 mm {0.04-0.07 in}
thickness of sealant ...