1. Disconnect the negative battery cable..
2. Partially peel back the seaming welt.
3. Remove the liftgate upper trim..
4. Disconnect antenna feeder No.3 connector..
5. Visually inspect the glass antenna for damage.
6. Verify that the continuity between the glass antenna terminals is as indicated in the table.

If not as indicated in the table, repair the glass antenna..

Glass Antenna
Glass/Windows/MirrorsSae Standards
In accordance with new regulations, SAE (Society of Automotive Engineers)
standard names and abbreviations are now used in this manual. The table below
lists the names and abbreviations that have been used in Mazda manuals up to
now and their SAE equivalents.
...
Clutch Release Collar Inspection [C66 M R]
CAUTION:
Do not clean the clutch release collar with cleaning fluids or a steam cleaner
because it is filled with grease.
Operation Inspection
1. Turn the collar while applying force in the axial direction, and inspect for
sticking, excessive resistance, and an abnormal noise.
...
Front Door Speaker Inspection
1. Disconnect the negative battery cable..
2. Remove the following parts:
a. Inner garnish.
b. Front door trim.
3. Disconnect the front door speaker connector..
4. Verify that the resistance and continuity between the front door speaker terminals
is as indicated in the table.
...