As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ALL CABIN TEMP ZONES VERY DIFFICULT TO CONTROL. FLUCTUATES FROM VERY COLD TO VERY HOT. ACFT GROUNDED. FOUND CABIN TEMPERATURE SENSORS FWD AND AFT VERY DIRTY. REMOVED AND REPLACED THE TEMP SENSOR FILTERS. CLEANED CABIN TEMP SENSOR FORWARD, AFT, AND FLIGHT DECK, IAW AMM 21-61-10. RAN CABIN AIR WITH GROUND GATE AIR AS WELL AS PACK AIR. OPS CHECKED GOOD.