Thanks, I found the answer to my own question. Seems I checked the defrost thermostat right after defrosting the freezer with my hair dryer. It showed an open (o) because the the components were not cold enough during the test. Now that it's been running I get a (s) for shorted or closed. The thermostat should be shorted or closed anytime it is cold and it's safe to run a defrost cycle. I need to order a jazz board.