Mazda RX-8 Workshop Manual page 39

Inspection
When a tester is used to inspect for continuity or measuring voltage, insert the tester
probe from the wiring harness side.
Inspect the terminals of waterproof connectors from the connector side since they cannot
be accessed from the wiring harness side.
CAUTION:
Terminals
Inspection
Pull lightly on individual wires to verify that they are secured in the terminal.
To prevent damage to the terminal, wrap a thin wire around the tester
probe before inserting into terminal.