HVAC problem
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Joined: Jul 2011
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HVAC problem
I've an 86 F150 reg cab XLT Lariat. 302 EFI with AOD. My problem is the HVAC system. It will only blow out of the dash vents. I've been told that when it defaults that it will switch to defrost only. I've done some minor diagnosing a few yrs ago but as this is just my farm truck and never goes on the road it nae
ver really was an issue but I am laid off and wanting to see if I can fix this while I have some spare time. cannot hear any vac leaks and truck runs pretty good for having 175k on the meter. Any ideas ?
ver really was an issue but I am laid off and wanting to see if I can fix this while I have some spare time. cannot hear any vac leaks and truck runs pretty good for having 175k on the meter. Any ideas ?
Moderator
Joined: Nov 2007
Posts: 22,415
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From: Denver Metro Area, CO
Welcome to FTE.
There are some threads stuck to the top of this forum, they have Read First next to them.
One of them is the Tech Tips sticky, it contains links to all sorts of good information both from FTE and other places.
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This might help get you started:
Ford Truck Enthusiasts Forums - FAQ
There are some threads stuck to the top of this forum, they have Read First next to them.
One of them is the Tech Tips sticky, it contains links to all sorts of good information both from FTE and other places.
As for searching, you can
- search just this forum
- search within a specific thread
by clicking on the respective search term which will be located on the RH side near the top, just above the red icons used to give Reputation points or report a post to the admins.
You can also search all or just a part of FTE by using the Advanced Search, a link is available up at the top near the middle of the page.
This might help get you started:
Ford Truck Enthusiasts Forums - FAQ
Lead Driver
Joined: Jul 2009
Posts: 6,477
Likes: 19
From: Sheffield, AL
There are 3 "blending doors" in the system. The 1st one is controlled by the servo motor located in the engine bay just in front of where the glove compartment is. This door determines "inside/recirculate" or "outside/fresh" air. The second one [which Chris talked about when he mentioned piano hinge] is the one which controls whether the air stream is directed to "vent" or the third door, which directs the air stream to either "defrost" or "heat".
Most likely, the original plastic hinge of the 2nd door is broken and the door is stuck in the "vent" position.
Hope this helps!
Most likely, the original plastic hinge of the 2nd door is broken and the door is stuck in the "vent" position.
Hope this helps!
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