'97 Suburban Rear AC Blows Warm

UPDATE: I should have flipped through a few more pages. I found a good post.
http://www.automotiveforums.com/vbulletin/showthread.php?t=570496


My front blows very cold air, but my rear blows warm air. I really don't know where to start. I checked all the fuses I could find. I tried to control the rear air with the front controls and the rear controls.

Where does the cold air for the rear get vented to the back?

Thanks!