What was found
DURING FLIGHT THE FLIGHT DECK BECAME HOT AND INDICATED ABOUT 40C WITH THE TEMP SELECTER ON FULL COLD. WE FOLLOWED THE QRH AND TURNED THE TRIM AIR SWITCH OFF. THEN THE FLIGHT DECK TEMPATURE COOLED AND EVERYTHING OPERATED NORMALLY. THE CABIN TEMPATURE WAS NORMAL THE ENTIRE FLIGHT. GROUNDED - YES. BITE CHECKED PACK TEMP CONTROL BOXES NO DEFECT FOUND. FOUND CONTROL CABIN TEMP SENSOR AND FILTER DIRTY. CLEANED SENSOR, REPLACED FILTER. OPERATED PACKS. NO DEFECTS FOUND. REF B737-900 FIM 21-61 TASK 861.