As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: RETURN BACK TO DALLAS DUE TO HIGH CABIN TEMPERATURE. WAS UNABLE TO GET CABIN TEMPERATURE BELOW 90 DEGREES. EMERGENCY DECLARED LANDED WITHOUT INCIDENT. MAINTENANCE L/H TEMP/TRIM VALVE INOP, REMOVED AND INSTALLED SERVICEABLE VALVE, OPS CHECK GOOD, TEMP IS GOOD FORWARD AND AFT CABIN, IAW AMM 21-51-16.