What was found
BOI- AFTER THE GEAR WAS SELECTED DOWN THE RED LIGHT FOR THE LEFT MAIN GEAR REMAINED ON. RIGHT MAIN AND NOSE GEAR INDICATED DOWN BUT LEFT MAIN REMAINED RED. FLIGHT CREW CYCLED THE GEAR TWO MORE TIMES WITH THE SAME RESULT. AIRCRAFT LANDED WITHOUT INCIDENT IN BOI WITH THE LEFT MAIN INDICATING RED. GEAR PINS INSTALLED AND AIRCRAFT FERRIED TO PDX FOR REPAIR. LEFT MAIN GEAR ACTUATOR REPLACED I/A/W MAINTENANCE MANUAL. GEAR OPS CHECKED GOOD ON GEAR SWING.