What was found
AIRCRAFT WAS GROUNDED: AFT CABIN TEMP CONTROLLER WILL NOT CONTROL CABIN TEMPERATURE IN AUTO. TEMPERATURE GOES FULL HOT WITH A SMELL OF BURNING PLASTIC IN FLIGHT DECK AND CABIN. REMOVED AND REPLACED AFT CABIN ZONE TRIM AIR MODULATING VALVE ((AALA202405232685)), PER AMM 21-61-21. ALSO REMOVE AND REPLACED AFT CABIN TEMP SENSOR ((AALA202405247575)), PER AMM 21-61-10. ALL OPERATIONAL AND LEAK CHECK GOOD, NO MORE SOF.