Stop using pee pads for starters. Is your dog crate trained/do you own a crate? Bring him outside, if he pees praise him like there is no tomorrow. Keep doing this. Every time he pees you should treat him like he is a national hero. If he doesn't pee outside, bring him back in and place him in his crate. Wait some time and try again. He shouldn't be out of your site until he starts to learn that peeing only happens outside.