Heater Blowing Hot continually

Hello - newbie here but a 2002 Mk1 caddy owner for over 10 years. (yes they still made them down here to 2009)

Its midsummer in South Africa and 31C outside today. Not a good day to have the heater on continually on my caddy.

Its been in the workshop multiple times and had a new heater valve fitted, the heater matrix checked (its fine) and they are running out of ideas. On the last visit, the mechanic presented me with this he had removed from the vehicle  ; he referred to it as a heater switch, and said they are no longer available and is the likely cause. The unit doesnt seem to be OEM.

Question - does anyone know what this is (proper name) and where I could source one? Happy to airfreight it to stop me sweating into the seats!!!! Or any other ideas. Right now closing the vents gives me some peace!

many thanks in advance

As I have never seen one (2001) caddy mk1. I would suspect that it is the heater valve control unit.

Usually what I have seen is issues on later cars being the blend door being stuck open partially. thus overriding the a/c if equipped, and or the fresh air if not.

It is quite common to have an actuator go iffy causing the blend door to malfunction.