KJG92

I pulled the aftermarket pioneer out to go back to the stock head unit. I never liked the look of aftermarket. It sounds so much better in my opinion. One thing is the sub is not working. I've read that the Amos can go bad but where is it? I looked under the passenger seat and where the antenna is but I don't see anything. The changer works great and all 6 other speakers work but I'd like the sub as well. Is there a fuse somewhere for it? And what are the options if it is bad?