As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT REPORTED, WHEN NAV SWITCH ACTUATED SMOKE CAME OUT OF SWITCH WHILE MASTER SWITCH ON. INSPECTION FOUND THE NAV LIGHT SWITCH BURNT. MAINTENANCE REPAIRED WIRING IN LEFT WING TIP AND REPLACED NAV LIGHT SWITCH WITH NO FURTHER DEFECTS NOTED.