As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CRUISE, ALL CABIN EMERGENCY LIGHTS CAME ON EXCEPT LIGHTS AT DOOR 4L. NEW POWER SUPPLY AND BATTERY NO HELP. FOUND LOW VOLTAGE AT PIN 22 AT DM33407. SUSPECT FAULT IN WIRE BETWEEN D6222P AND DM33407. *S/D* REPLACED CORRODED CONNECTOR D6219P AND D6207J. ALSO, REPOSITIONED CONNECTOR TO MINIMIZE CONDENSATION IN FUTURE.