changed battery, blend doors are flapping, radio flashes on & off, no display for radio or heater controls
Can I ask what led you to change out your old battery? Did you change it or did someone else. Did you or anyone else try jumping the car? Did anyone hook up a charger to your old battery while it was still in the car? Was it extremely cold out if and when your old battery died? etc.
Your car may require some re-programming at a dealership for this problem, but common sense says to try disconnecting the battery for an hour or so, then reconnecting. Could work. The blend door actuators can get confused about whether they are closed or open, they don’t know what to do about it, so sometimes they have to be told which is which using a dealership scan tool. Some radios require a code be entered whenever the battery is disconnected. That’s to discourage radio theft. The thief may steal the radio, but then they can’t use it, or sell it. Often the code is written somewhere in the owner’s manual.
When re-connecting a battery, always connect the negative lead last.