What was found
CONT CAB ZONE TEMP ILLUMINATES ON MASTER CAUTION RECALL. EXTINGUISHES WITH MASTER CAUTION RESET. GROUNDED - YES. INITIAL EVALUATION, NO ZONE TEMP LIGHT ON MASTER RECALL. PERFORMED PACK BITE IAW B737-900 FIM 21-62 TASK 801. NO FAULTS FOUND ON PZTC1/2, GREEN VERIFY ON BOTH. RAN BOTH PACKS FOR 10-20 MINS, RE-BITE, NO FAULTS. CLEANED TEMP BULB IN FLIGHT DECK TEMP SENSOR IAW B737-900 AMM 21-61-10-100-801. FOUND TO BE DIRTY. REMOVED AND REPLACED CONT CAB TRIM AIR VALVE V143 IAW B737-900 AMM 21-61-21-000/400-801. LEAK CHECKS GOOD. PERFORMED PZTC BITE AGAIN, NO FAULTS. THIS CLEARS MEL 21-21G. SEAMC ANDY NOTIFIED. PLACARDS REMOVED. NO A/C CONFIG CHANGES.