Because the antenna system is equipped with a capacitor, the continuity cannot be checked. Therefore proceed the following simple inspection.
Turn the AM radio on.
Tune to the frequency that there is no broadcast and you will hear a buzzing sound.
Turn a work light on and shake it around the antenna rod. (around 10—20 mm {0.40—0.78 in})
CAUTION:
Use a fluorescent light type for the inspection. Accurate diagnostic cannot be done with a different type of light.

If a whirring sound from the speaker synchronized to the work light movement is confirmed, the antenna system is normal.
Coil Antenna Removal/Installation
Entertainment Personalization Features Setting ProcedureSupplier Identification Procedure [Audio]
Identification Using the Label or Inscribed Lettering
1. Disconnect the negative battery cable..
2. Remove the center panel..
3. Remove the audio unit..
4. Verify the supplier by referring to the label attached to each unit.
Verify Using the Diagnostic Assist Function
Without display
...
Push-Starting
Do not push-start your Mazda.
WARNING
Never tow a vehicle to start it:
Towing a vehicle to start it is
dangerous. The vehicle being towed
could surge forward when its engine
starts, causing the two vehicles to
collide. The occupants could be injured.
CAUTION
...
Interior Equipment (View A)
Door-lock knob
Turn and lane-change signal
Lighting control
Wiper and washer lever
DSC OFF switch
Tire pressure monitoring system set switch
LDWS switch
AFS OFF switch
BSM OFF switch
Headlight leveling switch
Outside mirror switch
Door-lock switch
Power window lock s ...