Take the appropriate action and verify that the warning light turns off.

Taking Action
Message Indicated on DisplayMazda 6 Owners Manual: Operation
System triggering conditions
The horn sounds intermittently and the hazard warning lights flash for about
30 seconds when the system is triggered by any one of the following:
Unlocking a door with the key, door lock switch, or an inside door-lock
knob.
Forcing open a door, the hood or th ...
Mazda 6 Owners Manual: Blind Spot Monitoring (BSM) Warning Indicator Lights/Display Indicator/ Blind
Spot Monitoring (BSM) Warning Beep
The Blind Spot Monitoring (BSM) or Rear Cross Traffic Alert (RCTA) system notifies
the driver of the presence of vehicles in adjacent lanes or at the rear of the vehicle
using the Blind Spot Monitoring (BSM) warning indicator light, the warning sound
and the display indicator (vehicles with mu ...