As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CRUISE NOTICED THE CABIN EMER LIGHTS FLASHING ON THEN OFF SPORADICALLY. TOGGLED THE EMER LIGHT SWITCH OFF THEN ARM POSITION WITH NO CHANGE. INSTALLED FWD CUSTOMER SUPPLIED TESTED BATTERY IAW AMM 33-52-01. PERFORMED OPS CHECK, OPS CHKD GOOD, NO DEFECTS NOTED. IAW AMM TASK 33-52-01-710-801-A.