1) Turn the ignition switch to OFF.
2) Using a tester, check continuity between the power supply CM and stop light switch.
Connector & terminal
5 door model
(B420) No. 1 — (B65) No. 2: (B65) No. 1 — F/B fuse No. 8:
4 door model
(B420) No. 1 — (B65) No. 4: (B65) No. 3 — F/B fuse No. 8:
Is there continuity?
Replace the power supply CM.
Repair or replace the harness.