As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IAH- FLIGHT 3969, EN ROUTE THE CREW NOTED THAT THE LAV SMOKE WARNING ILLUMINATED. NO INDICATION OF SMOKE OR FIRE FOUND, PULLED CB'S AS SPECIFIED IN QHR. MAINTENANCE REMOVED AND REPLACED THE SMOKE DETECTOR PANEL, PERFORMED A OPERATIONAL CHECK OF THE SYSTEM AND NO DEFECTS NOTED. THE AIRCRAFT WAS APPROVED FOR RETURN TO SERVICE.