What was found
AFTER TAKEOFF ON GEAR RETRACTION, ALL GEAR LIGHTS NORMAL. PERFORMED UPLATCH CHECK AND GEAR DOOR OPEN LIGHT ILLUMINATED. PERFORMED SECOND UPLATCH CHECK AND DOOR OPEN LIGHT AND LEFT GEAR UNSAFE LIGHT ILLUMINATED. FLIGHT RETURNED TO PHX AND LANDED WITHOUT INCIDENT. RIGGED UPLOCK ROLLER ASSEMBLY, OPERATIONAL CHECK OK.