What was found
EMERG EXIT SIGN/LIGHT: WITH THE MAIN AIRCRAFT BATTERIES CONNECTED, MOVING THE EMERGENCY LIGHTS SWITCH TO EITHER ON OR ARM, THE EMERGENCY LIGHTS DO NOT ILLUMINATE AT ALL. WITH MAIN AIRCRAFT BATTERIES ON, EMERGENCY LIGHTS ILLUMINATE WITH THE EMERGENCY LIGHT SWITCH IN THE ON POSITION BUT EXTINGUISH WHEN THE AIRCRAFT MAIN BATTERIES ARE TURNED OFF. SUSPECT DEPLETED EMERGENCY LIGHT BATTERIES. REPLACED EMERGENCY BATTERIES. IAW CE-680A MM 33-50-05 AND 33-50-00. OPS CHECK GOOD.