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 ProcedureStop Vehicle in Safe Place Immediately
If any of the following warning lights turns on, the system may have a
malfunction. Stop the
vehicle in a safe place immediately and contact an Authorized Mazda Dealer.
...
Trunk Lid Key Cylinder Removal/Installation
1. Disconnect the negative battery cable..
2. Remove the trunk lid trim..
3. Lift the clip in the direction of the arrow (1), and pull out the key rod
in the direction of the arrow (2).
4. Remove the nuts.
5. Remove the trunk lid key cylinder.
6. Install in the reverse order of r ...
Starter Inspection [Mzr 2.0, Mzr 2.5]
On-vehicle Inspection
1. Verify that the battery is fully charged.
2. The starter is normal if it rotates smoothly and without any noise when the
engine is cranked.
If the starter does not operate, inspect the following:
Remove the starter, and inspect the starter unit.
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