00 s-10 p'up

I'm trying to help out my brother, who just purchased a 00 s-10 x-cab p'up. The problem that he is having, is whenever he runs the air conditioning, his carpet on the pass side floor front, and rear gets wet. We went as far as pulling the wheel well, figuring the drain was plugged, but found no drain. Any ideas on how to fix?

There should be a black pipe with a rubber fliper on it on the firewall or some use a built in hole on bottom of evaporaror cover.