As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT PACK LIGHT LILLUMINATED DURING MASTER CAUTION RECALL. EXTINGUISHED WITH RESET. GROUNDED - YES. REPLACED CONTROL CABIN TRIM MODULATING VALVE REF B737-800 AMM 21-61-21. OPS CHECK GOOD. NO FURTHER DEFECTS NOTED. PLACARDS REMOVED, C/N 18028508 REMOVED. THIS CLEARS MEL 21-32B. SEAMC DAVE NOTIFIED.