ac blows cold out of only 2 vents

[freedo]

did a search and found some kinda similar issues but nothing exactly the same. its a 01 3.0 5spd with 220k on it. the 2 driver side dash vents will blow cold air, the passenger side middle vent will blow hot air, passenger side outer vent will blow luke warm. and the floor vents will burn your feet off. i have a feeling its the blend door but i havent found any good diy on how to access that to replace it. also want to verify if that is the real issue. im sure this has been discussed before but i was not able to find it. any links for the diy or any other suggestion on where to look would be greatly appreciated.