What was found
CABIN EMERG LIGHT: WITH EMERGENCY LIGHTS IN ARM POSITION, DURING ENGINE START WE GOT A CAS MESSAGE THAT SAID EMER LIGHTS NOT ARMED. WHILE INFLIGHT, EMERGENCY LIGHTS WERE FLICKERING WITH THE SWITCH IN THE ARM POSITION COMPLIED WITH SL 505-33-0005 AND FIM 33-50-00-810-801-A ISOLATED THE EMERGENCY LIGHT ISSUE TO THE AFT BATTERY. WE DISCONNECTED THE AFT BATTERY AND THE EMERGENCY LIGHTS OPERATED NORMAL. REMOVED AFT EMERGENCY BATTERY PIN 6450LS-00 SIN 1609. ACCESSED FWD EMERGENCY BATTERY. REMOVED AND REPLACED THE FWD EMERGENCY BATTERIES. COMPLIED WITH SATISFACTORY OPERATIONAL CHECK. REFERENCE AMM 33-52-01-000/400-80-A.