What was found
APPROX 3 MIN AFTER DEPARTURE THE RT WING TO BODY OVERHEAT LIGHT ILLUMINATED. FOLLOWED QRH PROCEDURES AND LIGHT EXTINGUISHED APPROX 2 MIN LATER. DURING TAXI & TAKEOFF PACK WAS IN AUTO POSITION, AND AFTER TAKEOFF POSITIONED PACK TO HIGH WITH OVERHEAT CONDITION OCCURING APPROX 1 MIN LATER. ACFT TURNED BACK & LANDED WITHOUT FURTHER EVENT. MX TROUBLESHOT OVERHEAT SYSTEM PER TSM 26-18-00. CHECKED LOOP RESISTANCE FROM M237 COMPARTMENT OVERHEAT CONTROL UNIT THROUGH PINS: 10-11 (8.4 OHMS), PINS 4-12 (11.4 OHMS), PINS 2-8 (5.9 OHMS), PINS 2-29 (6 OHMS), & PINS 13-27 (10.3 OHMS), ALL PIN RESISTANCE WAS WITHIN TOLERANCE. REMOVED AND REPLACED RT RAM AIR OUTLET DUCT IAW BMM 21-51-21, LEAK AND OPERATIONAL CHECK GOOD.