What was found
PRE DEPT FOUND APU DOOR STATUS MSG. RESET DOOR NUMEROUS TIMES. DOOR STUCK OPEN. SUSPECT ACTUATOR. DOOR SECURED CLOSED IAW MEL. REPLACED INLET DOOR ACTUATOR, NO HELP. DOOR DOESN'T OPEN, CRANKED OPEN MANUALLY & REMOVED CONNECTOR PLUG APU, STILL NO CRANK. CLOSED INLET DOOR & DISCONNECTED CONNECTOR PLUG. SUSPECT INLET DOOR SWITCH BAD. ALSO, CHK APU START SW P-N & IF ANYTHING OTHER THAN 3600-5929 RPL SWITCH. THX, SFOEPA. REPLACED APU START SWITCH IAW SFOEPA, NO HELP. REPLACED RELAY K176, NO HELP. FOUND APU BATTERY DEAD. REPLACED APU BATTERY AND APU BATTERY CHARGER. OPS ARE NORMAL.