There is likely nothing wrong with the unit. It only senses temperature from the fresh food section. If the garage is below 38 deg the unit will never turn on. The freezer stays cold as a by-product of the fresh food staying at the correct temp. To test that the unit turns on use a hair dryer on low and heat up the upper section of the fresh food. Best thing is to not store freezer goods when the garage temp is below 45 deg.
Thank you let me know if you find something else.
I think inside is best. Starting a cold compressor will cause it to run harder until it is warm. Other wise no freezer goods until spring. Beware though, long terms under 32 deg and you will freeze beer and soda in the fresh food area.