'97 Celica: Adding Power Windows

[Ando140]

I posted a message about this in the Audio/Electrical section and didn't get any replies, so I figured I'd give this section a shot.
My brother has a '97 Celica and would like to upgrade to power windows. He wants to have the factory power windows. So, he bought a couple doors off a Celica in a junkyard to get all the parts he'd need. The problem is, after he hooks everything up, it doesn't work. I haven't actually looked at it myself, but he said, his car appears to have all the wiring it needs (other than the stuff he had to pull from the doors he bought). So, the question is, what could be wrong? Does anybody have any experience with this, or any ideas on what could be causing the problem?
Thanks for any help.