What was found
PHX - PVR - EL - CREW REPORTED AFTER T/O, GEAR HANDLE RAISED UP. ALL GEAR LIGHTS EXTINGUISHED EXCEPT RIGHT GEAR LIGHT. RT GEAR RED LT REMAINED ILLUMINATE. ACCOMPLISHED GEAR LIGHT DISAGREEMENT CHECKLIST GOT 3 GREEN, NO RED LIGHTS. CREW DECLARED AN EMERGENCY AND RETURNED TO PHX. THE LANDING WAS UNEVENTFUL. THE CREW TAXIED TO THE GATE. MX REPLACED UPLOCK SENSOR S74 IAW M/M 32-61-21-4 AND CK'D SENSOR CLEARANCE PER 32-61-21-5. (.189 INCH). MX PERFORMED L/GEAR POSITION INDICATING AND WARNING SYSTEM TEST IAW 32-61-00-5. OPS CHECK WAS GOOD. THE A/C WAS RETURNED TO SERVICE.