What was found
ON FINAL, 400 AGL, RECEIVED A "TO LOW GEAR" VERBAL WARNING, LDG GEAR POSITION DETECTION SYS WAS IN POS "1", SWITCHED TO SYS "2" AND CONTINUED PERFORMED GO-AROUND. ON SECOND ATTEMPT, THERE WAS NO WARNING, ALL SYSTEMS SHOWED GEAR DOWN, AND LANDED. IND R PER TSM AND GPWS SELF TEST, LEVEL NR 5, FLT LEG HISTORY INDICATED, EXT FAULT GEARSWITCH FAULT (79GB). DOWNLOCK SWITCH P/N OF OLD/REMOVED SWITCH AS FOLLOWS-(141FLO1D3--DATE 6/92, CPN# 2310526). REMOVED AND REPLACED SAME PER A300-600 MM NR 32-00-00-4, OPS CHK NORMAL PER A300-600 MM NR 34-48-00-5-02.