As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT PACK LIGHT ILLUMINATED. ON RECALL, THE LIGHT GOES OUT WITH MASTER CAUTION RESET PUSHED. ACFT GROUNDED. PERFORMED PACK ZONE TEMP CONTROLLER BITE TEST. TEMP CONTROL VALVE FAILED OPERATIONS TEST. REPLACED THE CONTROL VALVE IAW AMM 21-51-10. OPS & LEAK CHECKED GOOD IAW AMM 21-51-10.