How to fix a Waceo cf50, faulty Thermo sensor.

I first had a fault with my Waceo freezing, the compressor was running flat out, this was due to the sensor either seperating from the plate or moisture damaging the sensor, I fixed this by buying a cheap digital themro sensor and cutting off the sensor and soldering it to the controller board and placing the sensor in the fridge (also sealed the sensor with silicon to stop moisture entering it), The sensor works on resistants so any moisture that gets in to it changes the ohms and the fridge gets a false reading. The waceo is encased in solid foam so you cannot access the existing sensor and the way to correctly fix this is by drilling the outer case plastic then carefully make a hole in the foam with a screwdriver and place a new sensor probe on the outside of the inner fridge plate.

My question is has anybody done this or had there fridge fix and can tell me where the hole was drilled?