I have a 1997 caravan. the air no longer works. Sometimes while driving the temp control is on cool but then all of a sudden heat will come out of the vents for about 12 minute and then go back to cool After driving awhile it will do this again. and keep blowing cool air most of the time with intermitent burst of really hot air. Sometimes i think i can hear what sounds similar to the blend door move under the dash without moving the lever.

Any idea whats wrong and how i can fix it. It gets very hot in the summer with no air and even hotter when the van starts blowing hot air in your face.
Thanks

 

doors are controlled by the hvac control head. If they move, it's because they were told to. Pretty big issue with the temp sliders reading incorrectly. Could have a poor contact in the potentiometer so with good contact you get cold and if poor contact exists, blows warm.

 

Tizzy, Is there anything i can do to try and fix it?