What was found
DIVERSION / DECLARED EMERGENCY. AT APPROX 18,000 FEET, THE AFT LAV FIRE / SMOKE DETECTOR SOUNDED. NO VISIBLE SMOKE NOTED. DURING EMERGENCY EVACUATION, FLIGHT ATTENDANT NOTED BURNING ELECTRICAL SMELL. COMPLIED WITH AIRCRAFT INSPECTION, NO DEFECTS FOUND. REMOVED AND REPLACED AFT LAV SMOKE DETECTOR.