This sounds like you have a blend door actuator that is not working right or the AC amplifier has gone out but to be sure here is the wiring diagrams and fuses that needs to be checked for power:
Fuse # 17, 27, 20, 40 and 50
Here are the wiring diagrams so you can see how the system works and the component locations.
Please run down these guides and diagrams and report back.
Images (Click to enlarge)
Friday, May 28th, 2021 AT 11:48 AM