What was found
REAR F/A REPORTS BURNING, PLASTIC ODOR, BURNING POPCORN ODOR. PULLED C/B, ALL F/A REPORTED ODOR MOVING FORWARD FROM REAR CABIN PROGRESSIVELY GETTING HEAVIER. DESCENDED WHILE PERFORMING ON PACK OFF 1 ON. NO CHANGES, DIVERTED. ON GROUND ODOR STILL EVIDENT, FAINT BY F/A AND MAINTENANCE PERFORMED CAB, ODOR SMOKE T/C IAW T/C 21-059-002. FOUND ROW 29-30, ABC OVERHEAD SIDEWALL LIGHT HOLDER LOOSE AND EVIDENCE OF ARCING, REMOVED BULB AND REPLACED COALESER SOCK IAW 21-20-02-990-811. OPS CHECK GOOD.