I've seen the other threads on this, but my problem is a little different. I've replaced the damper assembly and the thermostat. I don't see any ice build up on the coils or in the freezer. I can get the refrigerator plenty cold enough if I detach the control panel from the ceiling and let it hang down. This removes the damper, which seems to be working, from the airflow from the freezer. This is the only way I can get the refrigerator cool enough. If I reattach the control panel, the refrigerator warms up to about 40-45F and the freezer to about 20F. Here's the strange part. To reattach the control panel, you insert a short tube on the rear of the control panel into a hole in the back wall of the refrigerator. This acts as a support for the panel, but the tube is also hollow and appears to be an air path for air from the freezer. I don't know where the hole leads. However, when I insert the tube, the compressor will shut off. It eventually will come on again, but both compartments will begin to warm up. Thanks.

Thanks, Gene. I looked into it further. There is a lightcovering of ice all across the evaporator coils. The hole in the back of the refrigerator is the drain. It now seems to me that the problem is that the compressor doesn't run and shut off properly as if the thermostat isn't working correctly even though I replaced it.