The thermostat is located near the bottom ofthe support box. The thermostat is connected by two or three wires.Label the wire placement before disconnecting them. Remove thethermostat by loosening the clamp, by pushing back the retainerclips, or by removing the retaining screws.
Test the thermostat for continuityusing a multitesterset to the ohms setting X1. Start by testing the thermostat whenit has come up to room temperature (about 20 minutes after removingit from the freezer).
If the thermostat has two wirestouch one probe to each wire. You should get a reading of infinity.Chill the thermostat in the freezer for about twenty minutes andretest. This time you should get a reading of zero (continuity).
If the thermostat has three wires,number them 1, 2 and 3. Test combinations 1 & 2, 1 & 3and 2 & 3 and write down the results. Two of the combinationsshould yield a reading of infinity and one should yield a readingof zero. Now chill the thermostat in the freezer for about twentyminutes and retest. The combination that had a zero reading before,should now have a reading of infinity. One of the two other combinationsshould now yield a zero reading.
If the thermostat fails this test,it should be replaced.