As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON T/O BOTH FIRE WARN BELL CUTOUT LIGHT ON GLARESHIELD CAME ON DIM. FOUND WATER LEAKING DOWN BEHIND FIRE WARN DETECTOR ONTO WIRING TERMINALS. NO WATER ON ANY BLACK BOXES. REMOVED AND REPLACED APU FIRE AND OVERHEAT DETECTOR PWR UNIT PER MM 26-15-0. CLEANED AND DRIED PLUG PER GENERAL MAINTENANCE PRACTICES.