It's all the same system hvac, which stands for heating ventilation and air conditioning. I have seen some where the door is behind the glovebox but in mine it was below the radio. Before you go and pull the dash, take off the center dash bezel, glove box, air bag, and check the compressors to make sure the arms are still attached, as turned out to be my problem, instead of the blend door. The compressors are on either sides of the radio and I think there are 3 or 4. They are silver and look kind of like in line fuel filters. Watch the compressors and change the a/c settings to test each compressor and make sure all of them work, which you hear them hissing so they probably are, but check to make sure the arms are moving.
My problem was similar, I could get heat fine, but the a/c would only blow out of the defroster. I went straight in for the blend door, removing all the dash panels and dropping the steering column and dash, only to find that the blend door and motor were working properly. I found that the problem was not with the central blend door, but the smaller doors and the arms connecting them to their respective compressors. One of the arms on the right side was broken and had been since I got the car. The one on the left, however, got disconnected when I ran the RCAs and remote wires for my radio. Therefore I just reconnected the left one and just fabbed up an arm for the right side. So check the compressor arms, it could save you up to 12 hours of work!
The problem with those doors is that they direct the airflow to go to particular vents. When the arms connecting the doors to the compressors get broken off, it renders the doors useless and they fall to the open position, directing both your heat and a/c through the defrost vents.
If you find nothing wrong with the compressors, I don't know what to tell you other than check the blend door. Drop all dash panels, the dash itself, and I did the steering column for good measure and for easier access. This is necessary because the motor for the blend door is so conveniently placed. After all is removed the black plastic box below where the radio once was is your target. Some people tell you to cut out the door, but I'm not a big fan of cutting, so I just unscrewed the box, right down the middle and ripped open the box, but be careful because I found out that part is $400! And on top there was a small door and under it was my prize! Alas, the blend door! But there was nothing wrong with it.
So overall, the blend door fix is not necessarily a difficult fix, just a time consuming diy fix.
Ps sorry for the novel, but there's not much else to do at 1 am!
Hope this helps,
kstrayhorn
