Heating Stuck On / Busy Actuators - Do I need VAGCOM/VCDS?

[ck_uk]

Hi All

My first posting here, hoping to get some advice please. 

We have a 2003 A4 Avant which has developed an issue whereby the heating is on all the time. Hoping to try and resolve before the summer hits!

I've removed the glovebox and, even with the heating controls switched OFF on the dash, you can both hear and see the actuators trying to move. 

I've disengaged each of these in turn from the control arms just to make sure the arms are not seized. 

The flap over the main blower vent on the leftmost side, is at a 45 degree tilt. This doesn't change regardless of whether LO or HI selected when operating the system temperature. 

It seems to me that it could be an issue with whatever sends the control signals to the actuators, as they all seem to be trying to work at the same time.

My question is what next? Do I need VAGCOM diagnostics to see if there are any codes from the HVAC part of the system? I can only assume that even a decent OBD2 reader such as a Foxwell NT301 will not be able to read the codes from the HVAC?

Has the system got confused at some point, and needs a reset? 

It's notable that, with the ignition ON and the heating controls OFF, these actuator sounds can be heard every second for several minutes before the system goes silent.

Thanks in advance for any help