As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
EMERGENCY LIGHT SYSTEM TEST FAILED (AFT LT) WHEN TESTED FROM CIDS PANEL AT FORWARD FLIGHT ATTENDANT STATION. MAINTENANCE REMOVED AND REPLACED AFT LT EMERGENCY POWER SUPPLY UNIT (13WL) AND BATTERY PACK; EMERGENCY LIGHT SYSTEM TEST CHECKED GOOD.