AC randomly altering between heating/cooling & vents

[Mikethe1]

Hi,

1. Eddie Bauer 4.6 with auxiliary rear & top AC.
2. PCM went through repair 3 years ago (different problem, that repair fixed -> assumption is that PCM repair done properly).
3. Blend door actuators (driver & passenger) works fine, reacts to command from AC panel, no weird sounds indicating the common misalignment of wheels inside. However, looks like bad consistency to commands.
4. The mode door seems to move randomly, e.g. changing temperature, and then it moves so output goes to different vents. Inspected that while lowering the glow box to see that part.

I guess it's either bad circuits (wires) causing wrong voltage etc. signals from the controller, or controller issue.
Question is, is there a separate controller for the AC, or just the PCM? (Cause as I wrote, that one already "repaired").

Thanks,

 

[Run Amok]

Does this HVAC issue fall under the PCM? I thought the P was for powertrain?

 

[Mikethe1]

Does this HVAC issue fall under the PCM? I thought the P was for powertrain?

Inspecting PCM pinout, there are pins with A/C wording.

 

[Run Amok]

Inspecting PCM pinout, there are pins with A/C wording.

Post a solution when you find it. I'm curious to know if the PCM actually does have anything to do with this.