1993 Isuzu Trooper blinker

I have replaced all bulbs, the flasher, and the fuse. Every time I switch my left blinker on, it blows the fuse after 5 or 6 blinks. The right blinker blows it instantly. With both blinkers there is an electrical sound coming from the steering column. I replaced the 15 amp fuse with a 15 amp fuse. I've tried a heavier fuse and it works a little longer, but it heats up and blows eventually. I wasn't having any problems until I replaced my alternator.