Center Roof Antenna Inspection
1. Disconnect the negative battery cable..
2. Remove the rain sensor cover. (Vehicles with auto light/wiper system).
3. Disconnect the rain sensor connector. (Vehicles with auto light/wiper system)
4. Partially peel back the seaming welts.
5. Remove the following parts:
a. Sunroof seaming welt (vehicles with sunroof)
b. A-pillar trim.
c. Front scuff plate.
d. Rear scuff plate.
e. B-pillar lower trim.
f. Upper anchor of the front seat belt.
g. B-pillar upper trim.
h. Rear seat cushion.
i. Tire house trim.
j. C-pillar trim.
k. Map light.
l. Sunvisor.
m. Assist handle.
n. Headliner.
o. Center roof antenna.
6. Verify that there is no continuity between the center roof antenna terminals A and B using an ohmmeter.

7. Inspect for continuity between the center roof antenna terminals using an ohmmeter.
If not as indicated in the table, replace the center roof antenna.

The center roof antenna has a built-in antenna amplifier.
1. Disconnect the negative battery cable..
2. Remove the rain sensor cover. (Vehicles with auto light/wiper system).
3. Disconnect the rain sensor connector. (Vehicles with auto light/wiper system)
4. Partially peel back the seaming welts.
5. Remove the following parts:
a. Sunroof seaming welt (vehicles with sunroof)
b. A-pillar trim.
c. Front scuff plate.
d. Rear scuff plate.
e. B-pillar lower trim.
f. Upper anchor of the front seat belt.
g. B-pillar upper trim.
h. Rear seat cushion.
i. Tire house trim.
j. Trunk side upper trim.
k. C-pillar trim.
l. Map light.
m. Sunvisor.
n. Assist handle.
o. Headliner.
6. Connect the negative battery cable..
7. Switch the ignition to ON.
8. Turn the audio unit power to ON.
9. Tune in the radio.
10. Verify that voltage is B+ at the antenna amplifier terminal B.
If the battery voltage cannot be verified, replace the center roof antenna.
If the battery voltage can be verified, go to the feeder line inspection.
1. Remove the center roof antenna..
2. Verify that there is no continuity between the center roof antenna terminals A and C using an ohmmeter.
AM/FM type

AM/FM/SIRIUS type

3. Inspect for continuity between the center roof antenna terminals using an ohmmeter.
If not as indicated in the table, replace the center roof antenna.
AM/FM type

AM/FM/SIRIUS type

Test yourself
A quick Mazda 3 quiz: every answer comes with an explanation and a link to the manual page.