As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LAVATORY SMOKE LIGHT ILLUMINATED IN FLIGHT. FLIGHT ATTENDANTS REPORT NO SMOKE IN RIGHT AFT LAVATORY OR ANY INDICATION THAT A PAX HAD SMOKED. WATER HEATER WAS FAR HOTTER THEN THE LEFT AFT LAVATORY. FLIGHT ATTENDANTS TURNED OFF THE RIGHT AFT WATER HEATER. INSPECTED LAVATORY WATER HEATER PER AMM 38-13-01. ALSO REPLACED R4 SMOKE DETECTOR PER 26-14-01. TEST OK. OK FOR SERVICE. THE AIRCRAFT WAS GROUNDED.