Why are the heater, defrost, and mode not working?

Hi,

On these vehicles, there is a component called an AC amplifier. It is an electrical component that among other things, controls the airflow direction and temperature.

I attached a small portion of the wiring schematic below to show you how the amplifier and the dampers are controlled. Note that the highlighted wires are identified with the word bus. The bus is part of the CAN system. CAN stands for controller area network. Basically, all the modules/computers are tied together via a few wires.

Because of the design, I would recommend having the can-bus system scanned. That will retrieve diagnostic trouble codes regardless of the module storing them. With the codes, it will point us in the right direction. Otherwise, it will become a guessing game. I hope that makes sense.

Here is a video showing how the CAN is scanned:

https://youtu.be/InIlnsjOVFA

Let me know what you find or if you have other questions.

Take care,

Joe

See pic below.