[brcidd]

I can tell you that certain model cars are designed to "damper" the heat when air is asked for at the vents- Most designers avoid putting full heat in people's faces- to avoid that complaint-- likewise the systems are designed not to put full a/c cold on the defrost (windshield)- I know for a fact the later model U-vans have damper doors to restrict the flow of heat out the vents when on full hot- the actuators actually throw a secondary door to restrict the air flow out the vents when in full hot mode--I have had folks complain about this- and there is a TSB on it in the U-vans (Montanna, Silhouette, Venture) to disable the secondary door- if they complain. It is pretty simple- most folks want heat at their feet, and cool air in their faces- not heat in their faces. I once worked on a ladies car who wanted full a/c cold air to come out the defrost- but there was a whistling noise-turned out to be the secondary air dampner door at the defrost- You can look at your actuators and see if your vehicle has a secondary door- It will have two arms on it- and the TSB said to simply disconnect one of the arms....