What was found
FLT 740. DURING CRUISE FLT, APU HAD AN AUTO-SHUTDOWN FAULT LIGHT ILLUMINATE, WITH AN EICAS MESSAGE APU FAULT DISPLAYED. ACFT ALREADY HAD THE RIGHT ENGINE GENERATOR SYSTEM INOPERATIVE UNDER THE APPROPRIATE MEL PROVISIONS. THE FLIGHT DIVERTED TO FLL AND LANDED WITHOUT FURTHER INCIDENT. MAINTENANCE REPLACED THE RIGHT ENGINE IDG AND IDG PRESSURE RELIEF VALVE TO ALLOW THE AIRCRAFT TO CONTINUE SERVICE. MAINTENANCE REPLACED THE APU. VENDOR FOUND THE APU COOLING FAN FAILED.