As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT PACK INOP DESCENT RECALL CHECKLIST. GROUNDED - YES. REPEAT DISCREPANCY OF LEFT RAM AIR ACTUATOR FAULT LOGGED BUT RESETS DURING PZTC BITE. OBSERVED ACTUATOR DURING BITE AND NOTICED NO GLARING ABNOMALIES. REMOVED & REPLACED LEFT RAM AIR ACTUATOR PER B737-800 AMM 21-51-21. BITE TEST SHOWED FAULT IN RAM AIR ACTUATOR & LEFT PACK TEMP CONTROL VALVE. NO HELP. RETURNED LEFT RAM AIR AIR ACTUATOR TO MX PROCEDURES PER MEL 21-5C. ORIG SUBMISSION DATE: 12/29/2022