1. Verify that there is no continuity between the center roof antenna terminals A and C using an ohmmeter.
2. Inspect for continuity between the center roof antenna terminals using an ohmmeter.
Mazda 6 Service Manual: Generator removal/installation
Warning
When the battery cables are connected, touching the vehicle body with
generator terminal B will generate sparks. This can cause personal injury, fire,
and damage to the electrical components. Always disconnect the battery negative
cables before performing the following operation.
...
Mazda 6 Service 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 ...