More than likely you have an issue with one of the blend doors or the rod that connects them, or the actuator.
Here is a guide that shows how to replace the actuator on a different vehicle, but it is pretty standard.
Take a look at the picture below and it will show the detail you need on this system. Even though you have a single zone temperature control, you still have two blend doors, they are just connected by a rod that will move both doors together based on the movement of the actuator shown below.
Again, I am sure you have an issue with one or both of these doors or the rod. I would access the actuator and move the doors manually and see if you have even heat. If not, then it is not the actuator.
Run through this and let us know if you have questions on this. Thanks
Images (Click to enlarge)
Wednesday, October 13th, 2021 AT 1:51 PM