What was found
DURING FLIGHT 3478, DURING CRUISE AT 29000 FT THE YELLOW HYD HIGH TEMP LIGHT ILLUMINATED. FOLLOWED THE QRH AND SOME TIME AFTER TURNED OFF THE NR 2 ENG PUMP AC PUMP, AND THE PTU, THE HIGH TEMP ANNUNCIATOR WENT OUT. AIR RETURN TO DTW. MAINTENANCE REMOVED AND REPLACED NR 2 EDP IAW RJ85 MM 29-10-17. P/N ON OFF 521449, S/N ON F9717007, S/N OFF GOO1OO70. RAN SYSTEM FOR APPROX 1 HOUR, NO FAULTS NOTED. ALL CHECKS GOOD AT THIS TIME.