heater control unit

I've looked over existing threads to no avail. I have had no work performed on the Jeep other than my Oil Changes and Tire rotations in the past 2 years. The Climate control works perfectly for cooling but this morning we were leaving the Mountains in Virginia and it was cold enough to need heat...

I had a blinking light on my defrost light ( third switch from the left) on my heater control unit on start up for about 30 seconds then everything works fine.I replaced the control unit and all the blend door actuators still have the issue of blinking if any one has any information how to fix...