As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT IN BASE MAINTENANCE: DURING OPERATIONAL TEST OF THE EMERGENCY LIGHTS MULTI FUNCTION CONTROL DISPLAY UNIT SHOWS FAULT BATTERY/EMERGENCY POWER SUPPLY UNIT (14WL) MID RIGHT. PERFORMED THE VISUAL INSPECTION AND CLEANING OF THE BATTERY EMERGENCY POWER SUPPLY UNIT 14WL ON MID CABIN PER AMM 33-51-38-400-002-A.