How can I get the air to blow out of all of my vents?

I have a 1997 and a 1999 Caravan. In the 99 the righpassenger side blows only cold air. I have performed the calibration and still not working. Help??

On the 97 the air comes out of the defrost and rear vents only. On the rear vents it only runs cold are. I also have ran the calibration.

In both cases I believe that it has somethign to do with the blend door or actuator.

I am not a mechanic (by far) can you help?

Thanks