I have a Kenmore Side By Side model 106.53654300. The freezer side seems to work fine, but the refrigerator side isn't cooling. I put my hand near the vent between the freezer and refrigerator and there is a small trickle of cool air coming through it, apparently not enough to cool the fridge. I vacuumed the coils underneath the fridge and turned the unit off and then back on, but still nothing. What can I do next?