Rear heat not working

Hello, I'm Danny.

It sounds like you are having an issue with the rear auxiliary HVAC unit blend door actuator.It is a small electric motor that diverts air flow through the specific vents. Here is a tutorial showing what is involved to replace:

https://www.2carpros.com/articles/replace-blend-door-motor

I've attached step-by-step picture instructions below on how to replace and its location. I've also include the steps on how to re-calibrate the actuator after replacement.Hope this helps and thanks for using 2CarPros.