As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LANDING GEAR GREEN DOWNLOCK LIGHTS DID NOT ILLUMINATE AFTER GEAR EXTENSION. ALSO, UNSAFE LIGHTS WERE OUT. CREW PERFORMED GO-AROUND PROCEDURES AND VERIFIED VISUALLY THROUGH PERISCOPE THAT GEAR WAS DOWN AND LOCKED. MAINTENANCE FOUND RIGHT MAIN DOWNLOCK SWITCH CONNECTOR LOOSE. CLEANED AND RESECURED CONNECTOR, OPERATIONAL CHECK NORMAL ON GROUND.