All doors lock automatically when the lock side is pressed. They unlock when the unlock side is pressed.
Driver's door

Front passenger's door

To lock all the doors from an open front door, press the lock side of the door lock switch and then close the door.
NOTE
When locking the doors this way, be careful not to leave the key inside the vehicle.
Locking, Unlocking with Transmitter
Auto Lock/Unlock FunctionMazda 6 Owners Manual: Clutch switch inspection
Note
Perform the following inspection only when directed.
Continuity Inspection
1. Verify that the clutch switch is installed properly.
2. Disconnect the negative battery cable.
3. Remove the clutch switch.
4. Inspect for continuity between the clutch switch terminals using an
ohmmeter. ...
Mazda 6 Owners Manual: Intermittent concern troubleshooting
Vibration Method
If malfunction occurs or becomes worse while driving on a rough road or
when engine is vibrating, perform the steps below.
Note
There are several reasons why vehicle or engine vibration could
cause an electrical malfunction. Some of the things to check for:
- ...