As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT REPORT AFT CABIN EMERGENCY LIGHTS & SIGNS WON`T TEST. CORRECTIVE ACTION: T/S PER TSM R & R BATTERY PACK 13WC. PERFORMED MASTER RESET OF ALL A/C POWER SYSTEMS NOW OPERATIONS NORMAL. OK FOR CONTINUED SERVICE, REF A320 FAM AMM 33-51 & TSM 33-51.