I have a 1984 300 d turbo diesel and I cannot get my heater to shut off. So, my question is what could that possibly be? Could it be a fuse, or something else? I appreciate the help. I have encountered the same problem in the past but after a couple of days it will shut off when pressing the circle button if you know what I mean. It has always has worked in the past except last winter and a couple of days ago.