I have a Kenmore bottom freezer fridge. Can't find the manual. Is 7 the coldest setting or 1? We keep the fridge in our garage and with the artic temps we are having we need to adjust it.

Most refr's dont so well when the ambiant temps fall below 50 degrees. you should not need to adjust the controls must past the "midpoint" usually 4. but 7 is the coldest setting.
the best thing you can do is check what the actual temps are in your garage and if you can warm it up to above 50, then the unit should run properly again.
if the ambiant temps are too cold, the freezer wont be cold enough and the refr section will freeze things.