So I was putting in new subs and my battery was dead so i hooked it up to a battery charger and then all the power had left it (i put positive on positive and negative on negative). So i went and got my battery checked out and they said that the ground was bad on it so got another one and when i got home and hooked it up i got in and moved the key to the on position and all the power left it again. I do not know what the problem is please help me. I forgot to say it's a 91 4runner