What was found
BEFORE INITIATING START WITH GPU, EMER LIGHT SWITCH IN THE ARMED POSITION. AS SHED BUSSES COME OFF LINE DURING START, RECEIVED MESSAGE EMER LT NOT ARM YELLOW CAS. CYCLED THE SWITCH, AND CAS DISAPPEARS, HOWEVER, CABIN EMER LIGHTS ARE ON THROUGHOUT THE CABIN. IF SWITCH IS MOVED TO THE OFF POSITION, LIGHTS EXTINGUISH. IF MOVED TO ARM, EMER LIGHTS ARE ON.///SIGN-OFF/// REMOVED AND REPLACED #2 EMERGENCY BATTERY WITH TESTED UNIT. IAW EMB-505 AMM 33-52-01-710-801A, OPS CHECK GOOD.