@Baltic, is Htronic working ok with you?
Where did you place the controling unit (tsm 125) ? Somwhere hiden or so, that you see it? Can you maybe post a picture?
And where did your cable from the sensor exit the fridge box? Did you drill a new hole, or use some existing?
This year I replaced the faulty thermostath of vd15 with original one, but is now working even worse. So I bought TSM 125, which I will install this weekend, when I will recieve it on the boat. I'm currently cruising in Ionian.