i was using the fridge methord this year, it sat in the garden when not in use ( the electrics were inside nice and dry) when i wanted it i used wiped it over and used it,Might make a trip to the local tip tomorrow and see what I can come up with.
Would a fan heater with thermostat work in a fridge?
Hell you could even use a purpose designed cabinet heating element that wouldn't break, has enclosed electrical connections, lasts forever and gives out 100% heat and no light.Lots of options. Bulbs, lamps or resistors are all possibilities; mains, or transformered to a lower voltage, split mode convertors. It is only a small resistive load required, after all.