As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT CREW REPORTED CARGO FIRE EXTINGUISHER SWITCH LIGHT ILLUMINATE IN-FLIGHT AND DECLARED EMERGENCY. FLIGHT CREW RETURNED TO BLOCK WHERE IT LANDED SAFELY WITHOUT INCIDENT. MX TROUBLESHOOT CARGO FAN AND MEL THE ISSUE. MX PERSONNEL THEN REMOVED AND REPLACED RELAYS K0625 AND K0629. OPERATIONALLY CHECKED SATISFACTORY AND AIRCRAFT WAS RELEASED TO RETURN FOR SERVICE. (K)