Mazda RX-8 Workshop Manual page 2746

Diagnostic procedure
STEP
INSPECT FOR CONTINUITY BETWEEN BATTERY FUSE AND
1
INSTRUMENT CLUSTER
Turn the ignition switch to the ON position.
Measure the voltage at instrument cluster connector
terminal 2K.
NOTE:
Is the voltage 9 V or more?
INSPECT WIRING HARNESS BETWEEN INSTRUMENT CLUSTER
INSPECTION
Measure the voltage while shaking the
wiring harness between the battery and
instrument cluster.
ACTION
YesGo to the next step.
No Repair the related wiring
harness.