Upper defroster not working
Thread Starter
Burning Brakes
Joined: Aug 2000
Posts: 952
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From: Morgantown,WV USA
Upper defroster not working
My 78's blower & temp control is working just fine (good news) but it keeps blowing toward the floor regardless of what selection I choose.
I have been doing quite a bit of research on the subject from the archives on the forum and have a couple of questions.
I removed the side panel (of the console) and on the drivers side found the vacuum line that attaches what I think is the defroster valve. I replaced the vacuum source with a hose and drew vacuum from my miti-vac and the air flow shifted to the defroster. Thus, it appears that the door is working ok.
Based on what I have found thus far, does anyone have any suggested area I can look at to solve this problem?
I did locate the vacuum source from the engine (a small black hose on the drivers side of the car and cranked on it with the miti-vac and it would not hold vacuum. I do not know if this is relevent or not.
Any help is appreciated!
Dan
I have been doing quite a bit of research on the subject from the archives on the forum and have a couple of questions.
I removed the side panel (of the console) and on the drivers side found the vacuum line that attaches what I think is the defroster valve. I replaced the vacuum source with a hose and drew vacuum from my miti-vac and the air flow shifted to the defroster. Thus, it appears that the door is working ok.
Based on what I have found thus far, does anyone have any suggested area I can look at to solve this problem?
I did locate the vacuum source from the engine (a small black hose on the drivers side of the car and cranked on it with the miti-vac and it would not hold vacuum. I do not know if this is relevent or not.
Any help is appreciated!
Dan
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,116
From: Crossville TN
Putting your vac hand-pump on the supply line would not do much as you would have to pump long enough to draw-down the vacuum reservoir tank in the left front fender. Now, if that pump has a gauge and you were to leave it connected to that supply line and start the car, you could find out how much vacuum you have at that point (once it stabilized). If you have at least 12" Hg, the A/C vacuum system should work unless there is another leak somewhere. The most likely place for such a leak is at the distribution manifold on the left side of the heater/A/C control in your trans console.
