Dan - This is a total "shot in the dark", but I would look at the vacuum actuators that move the various flaps around to distribute the air to different functional areas. You may have a leaky vacuum hose, or the actuator may have quit that directs air to the defrosters. In my personal experience, I had my air conditioning seemingly quit on me during a rally with temperatures over 100 degrees F. Yikes! It turned out that there is a little plastic bellcrank that connects the vacuum actuator to the air flap, and the bellcrank had broken. I made a replacement from a small piece of aluminum plate, and have had no problems in that area since. Sometimes, it's the subtle things. Merry Christmas, and may God bless you all. Toby Peterson VIN 2248 Winged1