Thanks for advice Bryan, I have already tried top two button trick, but sadly no segments illuminate, It seems quite probable the suggestion from DAZ, defrost sensor faulting and staying in the defrost mode, however I am unaware of the method of test for these sensors. Are they N/O, N/C, PTC, NTC, several different options are available and all would give quite different outputs to a cpu. I assume these sensors are fed via a 5v common on plug CN30 via brown wire?(this is labelled Rdef and Fdef sensor on my diagram) but I am unsure of the location of these sensors, any help on what readings I should expect from these sensors and their location, BTW, feel free to ask for BMW help if any reqd lol, I seem to need a lot of help with fridges. Dave