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 EMERGENCY ESCAPE PATH LIGHTS AT ROWS 23, 24 AND 25 ON THE LEFT SIDE OF THE AIRCRAFT FAILED TO ILLUMINATE. MAINTENANCE FOUND POWER SUPPLY/BATTERY PACK MODULE M0954 TO BE DEFECTIVE AND REPLACED BOTH THE POWER SUPPLY AND BATTERY PACK. THE SYSTEM OPERATED NORMALLY AFTER THE COMPONENTS WERE REPLACED.