Not true. Assuming the ambient temp is warmer than the desired temp setting and the fridge/freezer mechanicals are in good shape an external temp controller will allow you to set the internal temp to any where between coold fridge temps and ambient.
If you are putting this in a garage in michigan then you will need a dual range and a heat source for fermenting during the winter.
But this is not the OP question he wanted to know what he would need to get it warmer then 51 deg. So I am assuming the outside temp is not keeping it warm enought inside the fridge.and for that he would need some way to heat it.
And the fridge. will not work for that U will need a heater And the fridge working together to keep the disired temp.