What was found
DURING APPROACH, NOSE LANDING GEAR GREEN DOWNLOCK LIGHT DID NOT ILLUMINATE AFTER GEAR EXTENSION. RECYCLED GEAR WITH SAME RESULTS. EMERGENCY EXTENSION PROCEDURES WERE UTILIZED AND AIRCRAFT LANDED WITHOUT INCIDENT. MAINTENANCE REPLACED NOSE GEAR LOCK SWITCH. ALSO, FOUND OVERCENTER LINKAGE OUT OF TOLERANCE. INSTALLED SHIMS, OPERATIONAL CHECK NORMAL.