What was found
DURING FLIGHT 3685 FROM MEM, THE GREEN HYDRAULIC HI TEMP CAUTION LIGHT ILLUMINATED. FOLLOWED QRH, AIR RETURN TO DTW. MAINTENANCE REPLACED NR 3 EDP IAW AMM 29-10-17 (201). OPS CHECK GOOD. P/N ON AND OFF 521449, S/N ON MX639940, S/N OFF MX619638. REPLACED GREEN HYDRAULIC TEMP SWITCH IAW AMM 29-33-11. OPS AND LEAK CHECK GOOD. P/N HE83273-1, S/N ON 1364TW, S/N OFF 1368TW.