What was found
FLT 4165 - CREW REPORTED THE CARGO DOOR WARNING LIGHT ILLUMINATED DURING FLIGHT. AIRCRAFT RETURNED TO AZO, LANDED 400 POUNDS OVERWEIGHT. AIRCRAFT WAS FERRIED WHERE CAK MAINTENANCE CONDUCTED AN OVERWEIGHT LANDING INSPECTION IAW MM 05-00-00. NO DEFECTS NOTED. MAINTENANCE ALSO INSPECTED THE CARGO DOOR WARNING SYSTEM, NO DEFECTS NOTED. SUSPECT CARGO DOOR MICROSWITCHES MAY HAVE FROZEN DURING THE NIGHT. AIRCRAFT RETURNED TO SERVICE.