As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LH PACK TEMP CONTROL VALVE FAILED. GROUNDED - YES. PACK ZONE TEMPERATURE CONTROL BITE SHOWS LH PACK TCV FAILED. REMOVED TEMPERATURE CONTROL VALVE PER B737-800 AMM 21-51-10-000-801. INSTALLED TCV PER AMM 21-51-10-400-801 PERFORMED GROUND VERIFICATION TEST PER AMM 21-51-10-400-801. PARA F GROUND VERIFICATION TEST PASSED.