What was found
ORD - FLT 357 - EN ROUTE LGA-ORD, UNSAFE NOSE GEAR INDICATION DURING APPROACH TO ORD. GEAR WAS DOWN 3 GREEN LIGHTS ALL MECHANICAL VISUAL INDICATION AGREE, ON SHORT FINAL. RECEIVED AUDIO LANDING GEAR ALONG WITH A RED LIGHT IN THE NOSE GEAR. THIS HAPPENED 304 TIMES WITH A QUICK FLASH OF THE RED LIGHT. DID A GO-AROUND AND CYCLED THE GEAR, ALL INDICATIONS WERE NORMAL AND THE NOSE GEAR FLASHED RED ONE TIME. LANDED ORD WITHOUT INCIDENT. SENSOR BAD, REPLACED NOSE GEAR DOWNLOCK SENSOR. SWUNG GEAR 4 TIMES. NO FAULTS NOTED. SYSTEM GROND CHECKED NORMAL OPERATION. (M)