What was found
AFTER PUSHBACK LH PACK LIGHT ILLUMINATED UPON MC RECALL. GROUNDED - YES. BLOCK TURNBACK FOR DUAL PACK LT'S ON RECALL. BOTH RESET W/ MASTER CAUTION. R/H PACK IS ALREADY ON MEL. RAN PZTC BITE ON BOTH PACKS NR 1 SHOWS RAM AIR ACTUATOR FAULT AMD NR 2 SHOWS TCV FAULT (THIS PACK). REF B737-800 FIM 21-62 TASK 801. BOTH RESET ON VERIFY. DUE TO HISTORY - PRECAUTIONARY NO MEL RELIEF. REMOVED AND REPLACED NR 2 TCV, OPS CHECK GOOD, BITE CHECK GOOD, LEAK CHECK GOOD IAW AMM 21-51-10. REMOVED AND REPLACED LT RAM AIR INLET ACTUATOR. OPS CHECKED NORMAL, BITE CHECKED GOOD IAW AMM 21-51-21. NO PACK LIGHTS ILLUMINATED ON RECALL.