As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING FLIGHT CREW OBSERVED WHAT SOUNDS LIKE A FAN HUMMING SOUNDS COMPARABLE TO WHAT IT SOUNDS LIKE WHEN ENGINES ARE OUT OF SYNCH. UPON LANDING PAX INFORMED US THAT SHE NOTICED SMOKE IN THE CABIN FOR 10 MIN PRIOR TO LANDING. TROUBLESHOT SYS, FOUND DEFOG BLOWER IN AFT CABIN AT FAULT. REMOVED AND REPLACED DEFOG BLOWER IAW MM CH 21-21-00. OPS CHECK GOOD.