Well, duhhh. Move the bloody garage fridge inside to the kitchen, silly.
I have neither qualifications nor experience, but my gut feeling is that it isn't electrical connections.
I'm imagining that there is one main cooling unit which provides cooling to both fridge and freezer, and the mechanism which distributes this between them has some kind of problem. I'm thinking the pipes which take chilled gas to the fridge block up, so that all the chilled gas goes to the freezer, thus causing the cold freezer and warm fridge. Or if there is some control mechanism to ration the chilled gas, this has a malfunction.