It sounds like you have blend door issues. I had a similar problem, that I took the ENTIRE dash out of the vehicle in hopes to resolve it, and it ended up being a small motor underneath the dash on the front passenger side of the vehicle. The motor has two phillips head screws in it, and it hard to reach. You must use a short screw driver to get it out, but this is what turned out to be my problem.
Its the motor that moves the blend door. Here is my thread.