2010 Dodge Challenger blinking rear defroster light

I have a 2010 challenger SE. The rear defroster light will blink for a minute or so every time the car is started. I have tried unhooking the battery for an hour and letting the computers reset and replaced fuses 14 and 28 and it still continues to happen.
Is there a way or need to calibrate the hvac controls on a challenger?
All the hvac controls work and the heat and AC work. When it first starts up and it is blinking the only vents that blow air are the dash vents, it doesn't matter what the vent control knob is set, floor, mix, defrost. After the light stops blinking, the air will redirect to where the knob is positioned. Any help would be greatly appreciated.