What was found
AIRCRAFT WAS GROUNDED: DURING FLIGHT THE FLIGHT ATTENDANT 3 AND 4 REPORTED BURNING ODOR NEAR 4L DOOR WHICH CAUSED NOSE AND THROAT IRRITATION. CLOSING THE VENT ABOVE DOOR 4L HELPED REDUCE THE SMELL. NO SMOKE OR FUMES WERE REPORTED WITH THE ODOR. ACCOMPLISHED WORK CARD 08L00021001. FOUND AFT DOOR AREA HEATERCLOGGED AND FOUND DAMAGED BURNT WIRING. CHECKED CONTINUITY INTERNAL FUSE. FUSE IS OPEN. REPLACED HEATER, PER AMM 21-45-01.