What was found
F/A REPORTS AIRCRAFT WARMS UP TO ROW 9 ROW 9 AFT STAYS VERY COLD STAYS COLD UNTIL AFT 4B ZONE TEMP CONTROLLER IS NEAR FULL WARM ON. PAST 3 O'CLOCK POSITION. IN THIS POSITION AFT CABIN TEMP & SUPPLY DUCT BOTH SHOW 30DEGS ON A/C PANEL BUT DOES NOT FEEL WARM IN AFT CABIN. GROUNDED YES. VERIFIED PASS CABIN AFT TEMP (AIR) NOT RESPONDING WITH CABIN CHANGE TEMP. CLEANED BOTH CABIN TEMP SENSOR FILTERS AND SENSORS TEST NML (GRND VERIFICATION) PER MM 21 61 10 000 802 BOTH ZONE TEMP CONTROLLERS BITE TESTS. NML PER FIM 21 62 62 TASK 801.