As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS FLYING IN HEAVY RAIN AND THE LEFT ENGINE FIRE WARNING LIGHT CAME ON AND PILOTS HSI FAILED, PILOT SHUTDOWN THE LEFT ENGINE AND LANDED. MX FOUND AVIONICS BAY VERY WET, SEALED NOSE AVIONICS BAY TO PREVENT MOISTURE FROM ENTERING. FOUND LEFT ENGINE FORWARD FIRE DETECTOR WIRING VERY WET, INSTALLED SEALED WIRE SPLICES ON FIRE DETECTION WIRING. DRYED AVIONICS BAY, HSI AND FIRE DETECTION WORKED NORMAL.