A/C Blows Hot and Cold Air on 2004 GMC Yukon

When air conditioner is turned on it blows cold air on passenger side and hot air on driver's side. Previously, after turning off ignition and restarting the A/c would work fine. Now, it won't correct itself...blows very hot on driver's side and cold on passenger side. How can this be fixed and how expensive? Thanks.

Asked by for the 2004 GMC Yukon
I hand the same problem, i had hot air in front and cold in the back.

remove the black plastic cover located right below your dash, covering the climate air vents .Locate the . . . I think the part name is call the Modedooractuator.This piece is made of plastic and had a electric connector attach. Well , I remove it and notice this vent door inside this part was not fully close so I clean it. , I spray a little lubricate and re-install it, Its been about 4 years and I never had that problem since. You may want to Google this" Moderdooractator"