I am having the usual fridge heating problems. When i plug in the appliance the figure 3 appears on the fridge temp display and then moves onto the the normal temperature setting showing the fridge side at 13 degrees. Whe i hold the 2 buttons for simultaneously the bottom segment of the fridge 7segment display suggests it a fan problem. The fan is ok and i have replaced the frost sensor. Is the 3 at start up an error code? and what should i change next.