What was found
ON CLIMB, LOWER AFT BODY OVERHEAT LIGHT ILLUMINATED ABOUT 10,000 FT. WHILE RETURNING TO AIRPORT, LIGHT WENT OUT ABOUT 1 MIN AFTER GOING TO IDLE THRUST ON ALL ENGS. ACCOMPLISHED RESISTANCE CHECKS IN KEEL BEAM AREA READING 3 MOHMS, AFT STAIR AREA READING 4 MOHMS AFT CARGO PIT READING 3 MOHMS. RAN AIRCRAFT AND FOUND LEAK IN AFT CARGO PIT NR 1 ENG DUCT (CENTER).