Ok. So I have researched the forums, and I can't for the life of me figure out my problem. My AC will only blow out the front vents. It will not blow out the defrost, or the floor. I have removed the battery and battery box to check the vacuum lines that run into the vacuum reservoir and they seem fine. All other threads I have found about this talk about the air blowing just through the defrost. I have the automatic climate control on my '03 screw. The temperature adjust works just fine, and the manual dial works fine to adjust the flow from hi/lo, but I can't get the flow to re-direct from just the front panel vents. Any ideas?

 

I don't know about our trucks for sure, but in my 02 explorer there is a little motor with a **** that comes off of it to shift the control door. That **** stripped and I had the same issue your having. It wasn't expensive just a PAI to replace. Maybe someone else knows if its the same type of control actuator.