What was found
EMERGENCY LIGHTS TURNING ON DURING FLIGHT AT SEATS 45D&G. AHM & CMCF ALSO SHOWS MMSG 33-12116 & 32-12127. FEW RESET ATTEMPTS HAVE BEEN MADE STILL HITTING. DUE TO HISTORY NEED TO REPLACE THE FOLLOWING 3 WELLS UNIT & LOAD/CHECK CORRECT SOFTWERE IS INSTALLED. FOR THE MMSGS M3351090 (CLASS 16), M3351WG04 (CLASS 27). FOR ISSUE AT 45 D&G M3351092 (CLASS 20). REF SSM DMC-B787-A-33-51-10-02A-054A-D. DMC-B787-A-33-51-13-08A- 054A-D. & AMM 33-51-07. PERFORMED EMERGENCY LIGHT SYS CONFIG WBU 16 AND WBU 27 NOT IN NETWORK & LS3722366 ELS DB & OPS NOT AVAILABLE. DURING INITIAL EVAL, FOUND WCU 16 WITH NO BATTERY INSTALLED. ONLY WCU 16 & WCU 27 NOT SHOWING ON SYS CONFIG, WCU 20 SHOWED UP NORMAL. R & R WCU 16 & WCU 27. AND INSTALLED NEW BATTERY TO WCU 16. SOFTWARES LOADED WITH NO ISSUES, NETWORK FULLY FORMED & ALL LIGHTS OPS CHECKED NORMAL, NO CURRENT FAULTS OR MESSAGES. REF AMM B787-A-33-51-00-00C-320A-A & AMM 33-51-07.