As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FWD CABIN EMERGENCY LIGHTS FAIL TO ILLUMINATE DURING TEST WHEN CIRCUIT BREAKERSS 1WL (H5) & 2WL (H6) WERE OPENED. R & R EPSU BATTERY IAW AMM 33-51-38-000-002-A & 33-51-38-400-002-A. OPS CHECKED GOOD IAW AMM 33-51-38-710-052-B, & 33-51-00-710-057-A.