What was found
ON APPROACH INTO ISO WHEN THE GEAR WAS SELECTED DOWN, THE N/G DOWN AND LOCKED LIGHT FAILED TO ILLUMINATE. ABORTED APPROACH RECYCLED THE GEAR AND STILL NO N/G IND. DECLARED EMERG AND DIVERTED TO RDU. CAPT DID A FLYBY AND THE TOWER VERIFIED THE GEAR WAS IN THE DOWN POSITION. ON SHORT FINAL, THE N/G DOWN LIGHT ILLUMINATED. THE A/C LANDED W/O INCIDENT. SHUT THE A/C DOWN AND ATTEMPTED TO DEPLANE PAX, BUT THE MAIN CABIN DOOR COULD NOT BE OPENED. F/O DEPLANED PAX THRU EMERG EXIT. A/C WAS JACKED UP AND THE L/G IND SYS FUNCTION TESTED. ALL IND NORMAL. REPLACED N/G DN LOCK SW. THE SW WAS TESTED. CABIN DOOR LINKAGED WAS CLEANED AND LUBED. DOOR CYCLED INSIDE AND OUTSIDE W/O PROBLEMS. A/C RETURNED TO SERV. (M)