Makes clicking noise when trying to get heat up front on 2006 Ford Explorer

This only happens when I turn the dial over to warm or hot air. As of now it will only blow out cold air. The rear blows hot air just fine. But only cold air up front.

2 answers
The termperature blend door actuator or the plenum case itself is at fault. Unfortunately, the dash must be pulled back and accessed to inspect then repair.
auctu whater motor in dash