What was found
JAX - FLT 880 - EN ROUTE FLL-PIT, WITH THE LEFT IDG ON MEL AND THE APU OPERATING, THE CREW RECEIVED INDICATIONS THAT THE APU HAD PERFORMED AN AUTO-SHUTDOWN. THE CREW TRIED UNSUCCESSFULLY TO RESTART THE APU. THE FLIGHT DIVERTED TO JAX AND LANDED WITH NO FURTHER INCIDENT. MAINTENANCE IN JAX REPLACED THE INLET DOOR PROXIMITY SENSOR DEFECTIVE AND REPLACED IT. SUBSEQUENTLY, THE DOOR INLET ACTUATOR WAS REPLACED DUE TO THE APU INLET DOOR NOT OPENING. (M)