What was found
THE NOSE GEAR GREEN LIGHT DID NOT ILLUMINATE WHEN GEAR WAS EXTENDED ON FINAL APPROACH TO EWR. THE RED LIGHT WAS ON, A MANUAL GEAR EXTENSION WAS PERFORMED DURING GO-AROUND AND THE GEAR WAS VISUALLY CHECKED THROUGH VIEW PORT. THE GREEN LIGHT ILLUMINATED ON SECOND APPROACH WHEN FLAPS WERE SET TO 30 DEGREES FOR A NORMAL LANDING. MAINTENANCE INSPECTED THE NOSE GEAR ASSEMBLY AND PROXIMITY SWITCH WIRING WITH NO DEFECTS NOTED. THE NOSE GEAR WAS SWUNG FOUR TIMES AND THE FAILURE COULD NOT BE DUPLICATED. THE LANDING GEAR ACCESSORY UNIT WAS REMOVED AND REPLACED AS A PRECAUTIONARY MEASURE IAW MM 32-09-100.