What was found
GROUND CREW REPORTED THAT WHEN POWER IS REMOVED FROM THE AIRCRAFT, THE EMERGENCY LIGHTS IN THE BACK HALF OF THE AIRCRAFT COME ON AND WILL NOT EXTINGUISH. REMOVED FROM SERVICE. PERFORMED A GVI OF THE CONNECTORS AND NOTED PIN 4 OF CONNECTOR 3351-P5 WAS PUSHED BACK AND NOT LOCKED AT THE AFT BATTERY PACK. RESEATED THE PIN SECURELY. PERFORMED AN OPS CHECK IAW 33-51-00-710-802. OPS GOOD. THE AIRCRAFT WAS RETURNED TO SERVICE.