What was found
COCKPIT TEMP SELECTOR UNRESPONSIVE, FULL AUTO HOT POSITION PROVIDES MARGINAL COCKPIT HEAT. FULL MAUNAL HOT ALSO UNRESPONSIVE. TURING TRIM AIR OFF, RESTORES TEMP SELECTOR SWITCH TO NEAR NORMAL OPS. ACFT GROUNDED. BITE ZONE TEMP CONTROLLERS, NO FAULTS. RAN LT PACK, VERIFIED DEFECT. FOUND FLT DECK TEMP SENSOR FILTER EXTREMELY CLOGGED, CLEANED FILTER. PERFORMED TRIM AIR OPERATION TEST REF MM 21-62-00-000-801 CYCLED SELECTOR TO ALL RANGE, INDICATOR & AIR TEMP MOVES ACCORDINGLY.