What was found
(AIRCRAFT NOT GROUNED) DURING WEEKLY INSP (W/O 549885), FOUND EPSU SYS TEST FAILS, EPSU 11WL EMER LIGHT. PERFORMED TSM 33-51-00-810-822-A, OBSERVED DURING TEST RED EXTERIOR LIGHTS FAULT ILLUMINATED. REPLACED EPSU BATTERY IAW AMM 33-51-38-000-002-A / AMM 33-51-38-400-002-A, OP CHECK GOOD IAW AMM 33-51-00-710-001-A AND IAW AMM 23-73-00-740-005-B.