Refrigerator/freezer not working

I have a side-by-side. Both the freezer and refrigerator stop working off and on. Just the bottoms of both compartments are cold. It stops working for a few hours or a couple of days, and then starts working again on its own. Then it goes off again, etc. When it is working, everything is fine - cold air is circulating in both compartments, and the the ice maker and water dispenser work. When it’s not working, I can still hear a motor running in the back of the unit, but no cold air is present inside and the water dispenser stops working. I vacuumed the back of the unit under the cardboard, but it didn’t help. This has been going on for 3 weeks. I had 2 repair appointments setup, but on the days of the appointments, the appliance worked. Can this be an electrical problem? Possibly a short somewhere in the wiring, where it turns on and off and then on again? Any ideas?