As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CAPT'S WINDSHIELD AIR FAILED. CREW COMMENTS: AT FL330. FOUND BOTH CAPT & F/O WINDSHIELD DEFOG VALVES FAILED CLOSED. MANUALLY OPENED BOTH VALVES PER MEL REQUIREMENTS, AIRFLOW NOTED ON BOTH CAPTS & F/O'S WINDOWS. REPLACED CIRCUIT BREAKER C10291 ON THE P180 PANEL, OPS CHECK GOOD PER AMM.