What was found
AFTER TAKEOFF, TAIL COMPARTMENT TEMPERATURE LIGHT AND MASTER WARNING LIGHT ILLUMINATED. LIGHTS REMAINED ON APPROXIMATELY 10 SECONDS AFTER COMPLETING MEMORY ITEMS ON CHECKLIST. EMERGENCY WAS DECLARED AND AIRCRAFT RETURNED TO DFW. AIRCRAFT LANDED WITHOUT INCIDENT. THE AIRCRAFT WAS GROUNDED. ACCOMPLISHED MCM CARDS 0930 SUMMER PREP, 26-96-11 TAIL COMPARTMENT TEMP HIGH LIGHT, 36-95-14 TAIL COMPARTMENT LEAKS AND 5770-20. REPLACED PYLON DUCT TO AUGMENTATION VALVE.