12v fridge/danfoss experts

I understand some danfoss fridges have a switch which can be manually operated to allow the compressor to still be used if the electronics fail.

If your electronics have bitten the dust it may be possible to fit a short sensor tube bellows type mechanical thermostat as used in a caravan or home fridge. BOC GASSES sell them , around $14
All the probe has to do is sense the temp, it is adjustable, and the two contacts can be wired to interrupt to 12v dc supply.

The thermostats used on older car airconditioning condensers are also ones which turn on when the temp gets too hot and stop if the sense gets too cold. They are usually set to prevent the evaporator from freezing but keep very cold, which is exactly what you want to do. One of those may also be usable, easily ferreted out of an older car aircon at a wreckers or your mates yard.

Check out eBay, seller ozi_ideas. He sells exactly the controller you are looking for. I have two. One on an engel and one on a Waeco. Work brilliantly. Can send you pics if you like. If you are tech savvy they are easy to build.