What was found
MAIN CABIN TEMP HARD TO CONTROL WITH FWD & AFT CONTROLLERS ABOUT 10-11:00 O`CLOCK POSITION, AFT CABIN TEMP ABOUT 26-28C. AFTER 45 MINS AT FULL COLD AND SUPPLY TEMP AT 8-10C CABIN FINALLY COOLED TO ABOUT 21-22C. FWD AND AFT CONTROLLERS TO MAINTAIN 21C MUST BE ABOUT 8:30 TO 9 O`CLOCK POS. ACFT GROUNDED. FOUND FWD & AFT CABIN TEMP SENSOR FILTERS DIRTY. CLEANED BOTH FWD & AFT CABIN TEMP SENSOR FILTERS. OPS CK GOOD. REF AMM 21-61-06 & FIM 21-61, TASK 863.