1st off.....Model of that Dometic would be helpful
Moving thermistor.....that suggests you do not have 'adjustable temp settings" but an 'auto temp control' model
Unplug thermistor leads from lower circuit board (usually on upper left area of board....2 leads)
Run fridge for 12 hrs w/o thermistor...no temp sensing feedback to thermostat so fridge will cooling continuously.
Food compartment should get very cold provided circuit board is functioning properly and cooling unit is capable of full cooling