1. Remove the clock spring.
2. Inspect for continuity between the clock spring terminals using an ohmmeter.


Note
Clock spring adjustment
Passenger-side air bag cut-off indicator light removal/installationMazda 6 Service Manual: Rocking the Vehicle
WARNING
Do not spin the wheels at more than 56 km/h (35 mph), and do not allow
anyone to stand behind a wheel when pushing the vehicle: When the vehicle
is stuck, spinning the wheels at high speed is dangerous. The spinning tire could
overheat and explode. This could cause serious injuries.
...
Mazda 6 Service Manual: Location index
INTAKE-AIR SYSTEM
FUEL SYSTEM
Engine Room Side
Fuel tank side
EMISSION SYSTEM
Engine room side
CONTROL SYSTEM
...