As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: FLIGHT ATTENDANT REPORTED A TICKING NOISE FROM THE 3R DOOR NEAR THE PRESSURE WARNING INDICATOR. MAINTENANCE FOUND THE OUTPUT FROM EMERGENCY POWER SUPPLY UNIT 12WL TO ARMED LIGHT ASSEMBLY WAS PULSING. REPLACED EMERGENCY POWER SUPPLY UNIT 12WL (AALA202504164137) AND BATTERY (AALA202504161516) PER AMM 33-51-38. A SATISFACTORY OPERATIONAL CHECK WAS ACCOMPLISHED.