As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
EMERGENCY LIGHTS DO NOT COME ON WITH THE SWITCH IN ON. THEY DO COME ON IN ARM. HOWEVER, THE AFT OVER-WING AND THE LAV EXIT LIGHT DO NOT COME ON UNTIL SHIP POWER IS AVAILABLE. TROUBLESHOT DISCREPANCY DOWN TO #4 EMERGENCY BATTERY & CHARGER SYSTEM. REMOVED & REPLACED #4 EMERGENCY BATTERY & CHARGER SYSTEM WITH REPAIRED UNIT. OPS CHECK GOOD. IAW MM 33-50-10 FOR MX PERFORMED.