As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIR TURNBACK DUE TO LEFT MAIN GEAR UNSAFE LIGHT ILLUMINATED AFTER GEAR RETRACTION. UNSAFE LIGHT WENT OUT UPON GEAR EXTENSION. AIRCRAFT MADE AN UNEVENTFUL LANDING. REMOVED AND REPLACED L/R MLG SENSOR. GEAR SWING PER BOEING MM, OPS CK GOOD PER BOEING MM.