I have a 4 month old zu that goes on the pad when he is in a confined area indoors, but when I take him outside he does not go. What can I do?

Try taking a pad outside and getting him to go on it there. If he is comfortable doing it, then let him do it a couple of times and then try removing the pad and see if he will then go natuarally. He may think that the pad is the only acceptable place to urinate. Although this is unrelated, my dad had to build a "bridge" for our family poodle to use the sliding glass doors. I accidentally forgot to put the bridge down one day, and "Missy" jumped the sliding glass door track and never used the bridge after that. It is the same principle, I think.

Evertyime your pup starts to whiz inside use something to distract him( like shaking a bottle full of rocks) and this will get him to stop peeing, when he does bring him outside to finish. If he does praise him a whole bunch. Keep on doing this dogs learn things by repitition, and consistency.
Ohh... And its usually best if you have a chosen spot for the dog to ''go'' every time and that is where you bring him.

Good luck.