What was found
FSD - ON CLIMBOUT PASSING 15,000 MSL, THE LOWER AFT BODY OVERHEAT LIGHT STARTED FLASHING. BLEEDS WERE NR 1 ON, LT PACKON, NR 2 RT ON, RT PACK ON, NR 3 OFF, OVERHEAT LIGHT EXTINGUISHED WITHIN 5 SECONDS OF TURNING NR 3 BLEED ON AND SYSTEM TESTED GOOD. NO FURTHER ACTION TAKEN, LEFT BOTH PACKS ON WITH NR 1, 2 RT AND 3 BLEEDS ON. REPLACED FIRE AND OVERHEAT DECTECTOR CONTROL BOX PER MM, OPS CHECKS GOOD.