As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE PILOT REPORTED THAT THERE WAS AN ELECTRICAL BURNING ODOR RESONATING FROM RIGHT AFT LAVATORY. THE AIRCRAFT WAS GROUNDED. FOUND THE LIGHT FIXTURE MELTED WITH SIGNS OF ARCING. INSTALLED A NEW MIRROR LIGHT SOCKET INBOARD POSITION AND REPLACED THE LAMP. OPS CHECKED GOOD IAW 33-26-03.