As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT PACK LIGHT ILLUMINATES WITH RECALL. EXTINGUISHES WITH MASTER CAUTION RESET. RAN QRH CHECKLIST. GROUNDED - YES. PERFORMED PACK / ZONE TEMP BITE TEST PER B737-800 AMM 21-61-00-700-806-002 LH PACK TEMPERATURE CONTROL VALVE (TCV). REMOVED LH PACK TCV PER AMM 21-51-10-000-801. INSTALLED LH PACK TCV PER AMM 21-51-10-400-801. PERFORMED INSTALLATION AND LEAK TEST PER AMM 21-51-10-400-801 PARA F. BOTH TEST PASSED.