As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING PREFLIGHT, THE LAVATORY SMOKE LIGHT CAME ON AND THE CARGO SMOKE DETECTOR LIGHT ON THE CENTRAL WARNING PANEL WILL NOT ILLUMINATE DURING ITS TEST. MAINTENANCE REMOVED CLEANED AND WARMED BOTH THE LAVATORY AND BOTH FORWARD AND AFT CARGO SMOKE DETECTORS.