What was found
FAILED EMERGENCY LIGHT SYSTEM BATTERY PACK M2503 (REF AAR NR 1000028367). REMOVED BATTERY PACK M2503 ON LEFT SIDE FORWARD CABIN IAW B737 AMM 33-51-06-960-805. INSTALLED BATTERY PACK M2503 ON LEFT SIDE FORWARD CABIN IAW B737 AMM 33-51-06-960-805 UP TO STEP 4.E.(5). (B). AND PERFORMED OPS. TEST. IAW B 737AMM 33-51-00-710-801. TEST GOOD. FAILED FUNCTIONAL CHECK DURING D CHECK IN RFD REMOVED BATTERY PACK M2503 ON LEFT SIDE FORWARD CABIN IAW B737 A MM 33-51-06-960-805. INSTALLED BATTERY PACK M2503 ON LEFT SIDE F ORWARD CABIN IAW B737 AMM 33-51-06-960-805 UP TO STEP 4.E.(5).(B ). AND PERFORMED OPS. TEST. IAW B 737AMM 33-51-00-710-801. TEST GOOD.