As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING INSPECTION DISCOVERED EMERGENCY LIGHT TEST FAILED THE LEFT EPSU. MAINTENANCE REMOVED AND REPLACED THE LEFT EPSU IAW AIRBUS AMM 33-51-58. OPERATIONAL CHECKS WERE GOOD. CONFIRMEND FAULT. VENDOR REPLACED THE S1 TEST SWITCH. UNIT WAS REPAIRED AND TESTED IAW CMM 33-51-12 REV 3.