I have a Westinghouse Imperial ET18GKXSW02. The coil in the freezer gets an ice buildup at the first corner of the coil were the bi-metalic senser is located. The tubing is cold to that point. The reast of the coil stayes warm. No cold air but fan and comp. run

Sounds like you have a sealed refrigeration system problem or a compressor that runs but is not pumping enough to get the job done. Usually weak valves in the compressor will do this.