Mazda RX-8 Workshop Manual page 3311

Is there continuity?
4 Disconnect the speaker
connector (2-pin) and inspect
the resistance of speaker.
Inspect the continuity
between the audio unit unit
wiring harness-side connector
terminal and speaker wiring
harness-side connector:
For rear
speaker
Terminal 1S
(LH+)—GND
Terminal 1U
(LH-)—GND
Terminal 1V
(RH+)—GND
Terminal 1X
(RH-)—GND
Audio unit—
front
speaker
Terminal 1A
(LH+)—
terminal B
Terminal 1C
(LH-)—
terminal A
Terminal 1D
(RH+)—
terminal B
Terminal 1F
(RH-)—
terminal A
Audio unit—
rear
speaker
Terminal 1S
(LH+)—
terminal B
Terminal 1U
(LH-)—
YesGo to the next step.
No Repair or replace the suspect wiring harness or
speaker unit.