Heater Problems?

[GDM Z28]

So this morning I walk out of the house and to my suprise it is 55 degree's. Im from Florida so that means I was freezing lol. Once the truck was warm i set the a/c to defrost and set the temp to 80. It warmed up quickly and i was happy. But as I was driving down the highway i felt a thing of cool air hit me so i put my hand up on the dash and the air was coming out cool (felt maybe a little warmer than out side air). So i turned the heat to 90 and it was really hot. Then i turned it down to 85 and it was warm but once turned back to 80 it was pretty cool. What would cause that?

[ryank1]

When you set the auto controls to the max, it will just blow hot air, below the max it uses a small air intake in the headliner and automatically adjust the air temperature to maintain the temp that it is set. So if you set it at 80 and it starts to approach 80 in the truck it will start blowing cooler air.

[MikeNH]

55 is nice out, toughen up.

 

 

And what the above poster said is accurate too.