I sounds like you have a bad defrost timer or you need to reprogram the one you have. I will need the model and serial number of your ice machine to determine if this is the right replacement part. Please call our sales team with this information so they can get you what you need. 1.888.388.6372
No, this part fits the CME250, CME 500, and CME500R. The part you want to stick with is the 12-1980-01 you mentioned. If you give our team a call at 888-388-6372 or live chat with us, we can special order it for you.