What was found
CREW REPORTED AFTER GEAR UP LATCH CHECK, THE GEAR DOOR OPEN LIGHT ILLUMINATED. REMAINED ILLUMINATED AFTER COM 5.32.15. CONTACTED FLIGHT OPS TO INFORM OF SITUATION AND DIVERTED. CREW DECLARED EMERGENCY. AFTER GEAR EXTENSION 3 GREEN DOWN AND LOCKED LIGHTS WITH EXTINGUISHED GEAR DOOR OPEN LIGHT. LANDED WITHOUT INCIDENT. THE AIRCRAFT WAS FLOWN UNDER SPECIAL FLIGHT PERMIT, WITH GEAR DOWN AND LOCKED, TO MAIN BASE. MAINTENANCE VERIFIED AND FOUND RT GEAR DOOR POSITION SWITCH MALFUNCTIONING. R & R SWITCH IAW MM 32-60-3. NO ADJUSTMENT REQUIRED. SYSTEM CHECKS GOOD IAW MM 32-60-3. ACFT RETURNED TO SERVICE.