What was found
RIGHT MAIN LANDING GEAR DOWN AND LOCKED INDICATION LIGHT FAILED TO ILLUMINATE WHEN GEAR SELECTED DOWN. THE FLIGHT CREW CYCLED GEAR, AND THE LIGHT ILLUMINATED. MAINTENANCE INSPECTED, CLEANED AND TIGHTEND THE RIGHT MAIN LANDING GEAR DOWNLOCK SWITCH CANNON PLUG, IAW DC-8 MAINTENANCE MANUAL 20-51-01. OPERATIONAL CHECKED GOOD.