I drive a 2000 Disco II with 48,000 miles. At the start of this winter, my heater stopped blowing out hot air when I was driving at speeds below 30 miles/hour or when I was Idling. The hot air only starts blowing when I reach around 50 miles per hour. But this changes on a daily basis....sometimes it doesn't blow hot air at all. Also, my fan seems to be on all the time. I tried talking sternly to it but to no avail. Any help would be great. This winter will not be pleasant without heat.