What was found
CONT CAB ZONE TEMP LIGHT ON RECALL. EXTINGUISHES WHEN MASTER CAUTION PRESSED. GROUNDED-YES. INITIAL EVALUATION, NO LIGHT ON MASTER RECALL. PERFORMED B737-800 FIM 21-62 TASK 801. BOTH PZTC'S SHOW GREEN ON ALL 3 STAGES ON BITE ON 1ST TRY. CLEANED CONT CAB TEMP SENSOR BULB, IAW B737-800 AMM 21-61-10-100-002. REMOVED AND REPLACED FILTER, IAW AMM 21-61-06-000/400-801. RAN BOTH PACKS FOR 10-15 MINS, ALTERNATING BETWEEN LT/RT PACKS AND HIGH/AUTO SETTINGS, OBEYING ALL PRECAUTIONS. NO FAULTS FOUND.