AC Blows Cold & Hot on 1997 Buick Riviera

When I turn the temp dial to (all the way) to run the AC the blower blows cold air through certain vents and hot air through the others?? Is this a relay or electrical issue or just a problem with the vent door?

Asked by for the 1997 Buick Riviera
Sounds like your blend doors are not working correctly. This is something that needs diagnostics.