Researched a bit, and deduced it was the control panel, since the buttons were not responding. Ordered the part and replaced the control panel after finding a technician's repair manual in the forum on this website. The instructions included in the manual were invaluable and saved me a lot of time. The actual repair was quick; putting the right code in to start the panel was a little more difficult. It was unclear how the code written in the manual should translate to the digital display, but after several tries, and making sure I entered each step correctly, it worked. Thankfully the problem is solved and we no longer have food freezing in our fridge.