Refer---slide on fins???

Hi everyone,
I know I should know this, however since we have been in the high desert learning a lot more about our refer. We have a BH 3670. Have had some problems with frost buildup and doing some defrosting today, what is the purpose of the slide on the fins in refridgerator section?? What position should it be in? towards the top of the fin or the bottom?
thanks
al

Keep the slide high on the fins for the colder settings.

The sliding thing is called a thermistor. It regulates the temperature of the refrigerator (not the freezer). I believe up is colder and down is warmer.