What was found
FLIGHT DECK TEMP GRADUALLY COOLING, WARM AIR NOT AVAILABLE WHEN SELECTING CONTROL CABIN TEMP SELECT KNOB TO WARMER TEMPERATURE. MOVING THE TEMP SELECT KNOB FULL HOT TO FULL COLD. NEEDLE ONLY MOVES +/- 2 DEGREES, NO WARM AIR FROM FOOT AIR VALVES. ACFT GROUNDED. INSPECTED THE CONTROL CABIN TEMP SENSOR MODULE, FOUND FILTER CLEAN AND FAN RUNNING. OPS CHECKED NORMAL, OPENS AND CLOSES SMOOTHLY TO TEMP SELECTION. NR 1 AND 2 PACKS ZONE TEMP CONTROLS SHOW NO FAULTS IAW AMM 21-61-00. PRECAUTIONARALLY REPLACED THE NR 2 PACK TEMP CONTOLLER IAW AMM 21-61-20. OPS NORMAL. GROUND VERIFICATION TEST PASSED.