old55pete Posted December 10, 2020 Share Posted December 10, 2020 Was going to a dr's appointment this morning and couldent get the defrosters to work. I kept playing with it and all I could get was hot air through the dash panel. I have the glove box out and the radio out and can see the vacume pots moving. I pulled the bottom heater pelenum and that door is moving open and closed. Where is the other door that deverts it from the dash to the defrosters? Link to comment Share on other sites More sharing options...
1986F150Six Posted December 10, 2020 Share Posted December 10, 2020 http://www.garysgaragemahal.com/hvac-systems.html See if this link works. Click on integral AC. Link to comment Share on other sites More sharing options...
old55pete Posted December 10, 2020 Author Share Posted December 10, 2020 http://www.garysgaragemahal.com/hvac-systems.html See if this link works. Click on integral AC. If some one knows, is the door with the part number 18A361 the diverter door that sends the air up to the defroster? Thanks Dave, I saw those when I was looking the system up. Un fortunatly there is no function description to go with part numbers and diagrams. Link to comment Share on other sites More sharing options...
kramttocs Posted December 10, 2020 Share Posted December 10, 2020 If some one knows, is the door with the part number 18A361 the diverter door that sends the air up to the defroster? Thanks Dave, I saw those when I was looking the system up. Un fortunatly there is no function description to go with part numbers and diagrams. I think this picture makes it the easiest to visualize the flow: [ignoring the Mix position] 18A361 (mode) impacts flow between dash (vent) and defrost/floor If 18A361 is closed off to the vents, then 18A478 directs flow between defrost/floor. Sounds like you've ran into the problematic plastic hinge failure on the mode door. A number of us here have done this repair within the past year or two. Some out of truck and some in Karl on FTE did an excellent guide on this From his opening paragraph: If your '80-86 Ford truck has factory air, you can expect the following failure to happen at some unspecified time. Your windshield will fog over on the inside, and when you select "Defrost" and turn up the fan, practically all the air blows out the registers on the face of the dash, instead of from the defrost nozzles. Edit: corrected the name of the door to 'mode' as opposed to 'blend' which is the cable actuated temp door Link to comment Share on other sites More sharing options...
1986F150Six Posted December 10, 2020 Share Posted December 10, 2020 If some one knows, is the door with the part number 18A361 the diverter door that sends the air up to the defroster? Thanks Dave, I saw those when I was looking the system up. Un fortunatly there is no function description to go with part numbers and diagrams. I am stretching it here, but I believe there is a servo motor nearer the steering wheel which has two vacuum hoses going to it. My son had a stereo head unit installed and then began to have issues. I removed the radio and saw the servo to the left. His issue was a vacuum leak and was corrected when I reattached a hose which had been knocked off. Link to comment Share on other sites More sharing options...
old55pete Posted December 10, 2020 Author Share Posted December 10, 2020 I am stretching it here, but I believe there is a servo motor nearer the steering wheel which has two vacuum hoses going to it. My son had a stereo head unit installed and then began to have issues. I removed the radio and saw the servo to the left. His issue was a vacuum leak and was corrected when I reattached a hose which had been knocked off. Dave, I have the radio and the glove box out and can see the vacume motors working. I was looking at the fact that the door that cant be seen was the one that failed, the 18A361 door. As Scott so kindly pointed out, the only door you cant see move. Link to comment Share on other sites More sharing options...
1986F150Six Posted December 10, 2020 Share Posted December 10, 2020 Dave, I have the radio and the glove box out and can see the vacume motors working. I was looking at the fact that the door that cant be seen was the one that failed, the 18A361 door. As Scott so kindly pointed out, the only door you cant see move. If I were you, Steve, I would listen to Scott! Link to comment Share on other sites More sharing options...
kramttocs Posted December 10, 2020 Share Posted December 10, 2020 If I were you, Steve, I would listen to Scott! I don't know - I am crossing my fingers that I am wrong. Would be much better if it wasn't that mode door failure. Link to comment Share on other sites More sharing options...
old55pete Posted December 10, 2020 Author Share Posted December 10, 2020 I don't know - I am crossing my fingers that I am wrong. Would be much better if it wasn't that mode door failure. Scott, in this case you are 100% correct. After reading through what that guy had to do to change that henge, it appears that is my next venture Thanks guys. Link to comment Share on other sites More sharing options...
old55pete Posted December 10, 2020 Author Share Posted December 10, 2020 Scott, in this case you are 100% correct. After reading through what that guy had to do to change that henge, it appears that is my next venture Thanks guys. Just as a heads up, I found that door NOS with new foam and all for $65.00. As I dont have a shop to work in, it will make it a little quicker. Link to comment Share on other sites More sharing options...
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