What was found
NR 3 ENG FIRE LP B-STATUS MSG CLEARS WITH FIRE TEST, BUT COMES BACK. TS681 AND TS682 READING LOW RESISTANCE AT 1.5KOHMS. ORDERED LOWER AFT LOOP. REPLACED NR 3 ENG LWR-AFT FIRE DETECTOR LOOP (TS682), NO HELP. EICAS SHOWS "ENG 3 - FIRE LP B" STATUS MSG. FIRE TEST FAILS WITH CMC MSG 26025. SUSPECT WIRING PROBLEM ON ACCNT AFTER ENGINE SHOP REPLACED OIL TANK & REROUTED WIRES IN THE VICINITY OF AFT-LWR FIRE LOOP AREA - 9 O'CLOCK POS LOOKING AFT BY THE OIL TANK. ENGINE REPLACED DUE TO FAILURE. AFTER ENGINE CHANGE ACCOMPLISHED FIRE TEST NUMEROUS TIMES. ALL TESTS PASS. NO FIRE LOOP STATUS MESSAGE DISPLAYED.