2004 Pontiac Sunfire ERLS Fuse

I have had troulbe with my ERLS fuse blowing. I had no trouble all winter and it began when I started to turn on my air conditioner. My question is what possilbe things could be causing this? How much would it be to repair? I have been just changing the fuse everytime but it's a pain and now I am just not turning on my air conditioner. This last time it happened I had not had my air conditioner on at all, if it isn't the air conditioner what else could it be?

Thanks