there are 4 wires going to the ice maker. there is a plastic sleve on the black wire that attaches to the side of the icemaker. Question, is this a thermo switch for power to the icemaker. i have ttied to detect power from the black wire using a test light between the black and the white and found no power. ( the new icemaker wont cycle ) ps. there is no door switch for the icemaker to interfer with the test.