As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING AN OVERNIGHT LINE CHECK THE UPPER DECK, AFT MOST EMERGENCY EXIT SIGN WAS FOUND TO BE INOPERATIVE. MAINTENANCE FOUND BATTERY PACK M6378 TO BE DEFECTIVE AND REPLACED IT. SYSTEM OPERATION WAS NORMAL AFTER THE BATTERY PACK WAS REPLACED.