What was found
AT TOP OF DESCENT, FLT ATTENDENT REPORTED SMOKE IN AFT RT LAV. CREW REMOVE BULB FROM LAV MIRROR LIGHT AND PULLED C/B ON P-18-3 PANEL FOR LAV MIRROR, ALL SMOKE STOPPED. AT GATE IN MSY WITH EXTERNAL POWER PLUGGED IN LIGHT STARTED TO SMOKE AND SPARK AGAIN. F/A SPRAYED FIRE BOTTLE ON AREA. ALL POWER WAS REMOVED FROM A/C. FLT CREW PULLED C/B IN E/E COMPT FOR LAV MIRROR LIGHTS ON E1-4.