As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON DEPARTURE FROM LAS EN ROUTE TO DFW AFTER RAISING THE LANDING GEAR AN UNSAFE RT HAND MLG UNSAFE RED LIGHT APPEARED AND REMAINED ILLUMINATED. PILOT CYCLED THE LANDING GEAR ONCE AT DIRECTION OF LAS MX. LIGHT REMAINED ILLUMINATED AND AIRCRAFT DIVERTED TO PHX. MAINTENANCE REMOVED AND REPLACED S00074 PROXIMITY SENSOR IAW MM 32-61-21-4 AND REPLACED CONNECTOR D4536P FOR DISCREPANT LOCKING FUNCTION PER BMM 20-61-11. NUMEROUS GEAR SWINGS PERFORMED WITH OPERATIONAL TESTS FOUND OK.