VW Tiguan AD1 retrofit remote heater activation

Since the German Enginers are as seems unable to use CAR NET to activate the auxiliary heater (Volvo did this like over 5 years ago with VOC) they decided to go for a third party solution... https://www.dfreeeze.de/

This can be fitted to my car since I have the heater and remote function by the fob. But I need to localize the T91 unit to connect the Defreeeze hardware. Anyone know where it is located?

Hi,

last shop I heart installed it on the right side inner quarter panel in the trunk as seen on the pictures. Pretty sure the T91 is there as well or at least the necessary signals.