What was found
FLT NR 582, FLL-HPN, CLIMBING THROUGH 2500' FEET F1 REPORTED HEAVY FUMES IN CABIN, QRH PROCEDURES WERE FOLLOWED, IFE/CSS POWER WAS TURNED OFF AS A PRECAUTION. RETURNED TO FLL. PERFORMED FIM TASK 21-20-00-810-801-A. FOUND NO C/B'S TRIPPED. NO FAULTS. ALL CABIN & COCKPIT LIGHTING OPERATIONAL. RAN PACKS ON APU & ENGINES. NO FAULTS OR SMELLS NOTED. C/W WITH ELECTRICAL ODOR SYSTEM INTEGRITY CHECK LTV MM 44-20-10. NO EVIDEBNCE OF SMOKE OR ELECTRICAL BURNING SMELL. OPS CHECK GOOD. ACFT OK FOR SERVICE.