What was found
THE EMERGENCY LIGHTS ASSOCIATED WITH THE #4 BATTERY PACK ARE NOT WORKING, EVEN AFTER TWO 30 MIN CHARGE CYCLES PER THE QRH. LIGHTS AFFECTED ARE AFT BULKHEAD EXIT, THE EXIT LIGHT ON FRONT PANEL OF LAV SEAT, & THE UNDER FLOOR LIGHTING IN FRONT OF LAV SEAT. THE EXIT LIGHT ABOVE LAV SEAT IS WORKING. THE 3 ABOVE MENTIONED LIGHTS DID NOT WORK IN BOTH THE ARM & ON POSITION. REQUESTED ALL FOUR EMERGENCY BATTERY PACKS BE REPLACED DUE TO NEW PN'S FOR EMERGENCY PACKS. R & R ALL FOUR EMERGENCY BATTERY PACKS IAW MM 33-50-06. PERFORMED OPS CHECKS IAW MM 33-50-00. OPS CHECKS GOOD. PERFORMED EMERGENCY LIGHTING INERTIA SWITCH OPS CHECK IAW MM 33-50-00. OPS CHECKS GOOD. NO FURTHER MAINTENANCE REQUIRED AT THIS TIME.