What was found
CONT CABIN ZONE TEMP LIGHT ILLUMINATED ON TAXI OUT. GROUNDED - YES. CONFIRMED DEFECT - PZTC BITE PER B737-900 FIM 21-62 TASK 801 SHOWED FLT DECK TRIM VALVE FAULT ON PZTC-2. ACCOMPLISHED INITIAL EVALUATION FOR FLIGHT DECK TRIM VALVE FAULT PER FIM 21-62 TASK 832 - INITIAL EVALUATION DID NOT CONFIRM FAULT - VERIFY TEST PASSED WITH NO FAULTS. FOUND CONTROL CABIN TEMPERATURE SENSOR FILTER CLOGGED WITH DUST AND TEMP SENSOR DIRTY. CLEANED SENSOR AND REPLACED TEMP SENSOR FILTER PER AMM 21-61-06-000-801 / AMM 21-61-06-400-801. PERFORMED CABIN TEMPERATURE CONTROL AND INDICATION - OPERATIONAL TEST PER AMM 21-61-00-700-807-002 - ALL TESTS PASS.