HVAC stuck on vent
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Lead Driver
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HVAC stuck on vent
In a bit of a bind. Away from home and the HVAC on my '84 is stuck on vent. No matter where I move the bottom lever, I always get full airflow from the vents. I don't hear any normal clunk as the doors move, either.
I thought the defrost door was spring-loaded so even with a loss of vacuum or failure of the selector, you'd still get defrost for safety.
Any quick ideas? Been having to wipe the windshield with a rag to get home.
I thought the defrost door was spring-loaded so even with a loss of vacuum or failure of the selector, you'd still get defrost for safety.
Any quick ideas? Been having to wipe the windshield with a rag to get home.
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From: Virginia
Find the vacuum line going in through the firewall over near the pass side hood hinge. It should be connected eventually to a tee that goes to a vacuum storage can or plastic ball under the hood. Disconnect this and see if it goes to defrost. If it won't default to defrost, you must have a mechanical problem with one of the doors.
P.S. Rain-x makes some impressive products, I have used their stuff on the outside of the windshield. They do also make some anti-fog stuff to put on the inside. I don't know if that would help out or not.
Also, you would be surprised how well the vent windows will clear the windshield if you are moving down the road. Turn the heat up, and crack open the triangle window vents, they will help keep the windshield clear inside. When they got rid of those little windows on cars and trucks, I think they made a big mistake.
P.S. Rain-x makes some impressive products, I have used their stuff on the outside of the windshield. They do also make some anti-fog stuff to put on the inside. I don't know if that would help out or not.
Also, you would be surprised how well the vent windows will clear the windshield if you are moving down the road. Turn the heat up, and crack open the triangle window vents, they will help keep the windshield clear inside. When they got rid of those little windows on cars and trucks, I think they made a big mistake.
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Home now and found all actuators operating normal. Peeled down the corner of the glovebox and I can see the vent door actuator cycle in and out as commanded.
It would seem the vent door hinge has broken, but I can't see it to confirm. How difficult is it to access the vent door hinge?
In a bind as I need the truck for work tomorrow. I'd be happy if I could just secure the vent door closed for now and finish the repair later.
It would seem the vent door hinge has broken, but I can't see it to confirm. How difficult is it to access the vent door hinge?
In a bind as I need the truck for work tomorrow. I'd be happy if I could just secure the vent door closed for now and finish the repair later.
Mountain Pass
Joined: Jun 2007
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From: Fort Worth TX
I have exactly the same problem on a 1980 F150 with factory AC. I haven't fixed it yet, but the reason is it appears I have to take the dash out, not just the dash cover, but the metal dash. In order to access this plenum that has that door.
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Remove the glovebox liner for access. Five screws. You'll want a ratcheting 90 degree screwdriver to get the three screws across the bottom.
This pic shows the view behind the glovebox liner. The silver can at the left is the vent door actuator. With the engine running (for a vacuum supply) you can move the panel select switch under the radio and watch this actuator move.
It's a little tough to see, but there's a tapered duct for the dash vents, about 6" wide. It hangs down on the aft side of the big plenum assembly. I fished a 7" x 7" piece of sheet metal in the narrow gap between the plenum and dash vent duct. The gap was sealed by foam tape, and the pressure from the foam is just enough to hold the metal. The piece of metal was painted white, and you can just make out the protruding edges in this pic.
Perfect? No. Thoroughly adequate for now? Darn tooting! I've got full airflow everywhere selected except for the dash vents.
Still dreading what it will take to do a proper repair on the vent door hinge, but this should work until this Arctic blast of weather has passed.
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From: Virginia
Here's something I found in a internet search.
Heat-A/C Panel Door Hinge Repair, 1986 - Ford Bronco Forum
Heat-A/C Panel Door Hinge Repair, 1986 - Ford Bronco Forum
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Lead Driver
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Here's something I found in a internet search.
Heat-A/C Panel Door Hinge Repair, 1986 - Ford Bronco Forum
Heat-A/C Panel Door Hinge Repair, 1986 - Ford Bronco Forum
Anybody got any good pics of what that door should like? I'm thinking of making a more substantial hinge than at that link, so pics of what to expect would be a huge help.
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Mountain Pass
Joined: Jun 2007
Posts: 117
Likes: 6
From: Fort Worth TX
Here's something I found in a internet search.
Heat-A/C Panel Door Hinge Repair, 1986 - Ford Bronco Forum
Heat-A/C Panel Door Hinge Repair, 1986 - Ford Bronco Forum
I knew there would be some benefit to me putting this repair off
.I don't mind a hack like that at all in this beast.
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Lead Driver
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Procrastination always has an immediate payoff!
I found more pics in this thread, from the Stickies. Scroll down to post #64:
https://www.ford-trucks.com/forums/1...pgrades-5.html
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Lead Driver
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The big thing I'm trying to discern is how the hinge/door is attached to the plenum. It looks like the hinge is attached to the bottom half of the plenum with two rivets. The hinge is secured to the top half of the plenum by two screws and nutclips.
It's too frigid out to tackle this anytime soon. Once the weather warms up at least to the point that boogers no longer freeze, I hope to work on it some more. In the meantime, the plate I added is working great to regain the defroster airflow.
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Lead Driver
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Thanks, I'll gladly take any pics you might have of that dash duct assembly that hangs down aft of the plenum. I'm still debating if I want to try removing it or cut an access hole through it.
Also, I'd like some nice close-up pics of your credit card(s), including the CCV number on the back. You did ask...
Thanks!
Also, I'd like some nice close-up pics of your credit card(s), including the CCV number on the back. You did ask...
Thanks!
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Lead Driver
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More random thoughts and request for pictures:
If I remove the cover on the aft side of the heater core, is there any room to snake my hand over to the panel door area?
How about from underneath if I remove the floor duct?
Been doing some professional grade pondering and have a PlanDuJour(tm), subject to change, as always.
The duct feeding the panel vents is split in two sections. If I remove three screws, the right side will be loose. I doubt I can remove it completely, but I just need to pull it aft and up a couple of inches. Then I can get in there with a pancake drill and remove those two rivets on the lower part of the hinge. I should be able to get the two bolts at the top with a ratcheting dogbone. Once I repair the hinge or fabricate something better, I will reinstall the door assembly with four bolts and no rivets.
Still hatching a scheme on how to reinstall the pin for the actuator end, on the inside of the door. That's why I'm wondering what sort of access is available via the heater core cover or the opening to the floor duct. I expect it the whole process will be like building a ship in a bottle, but I bet it can be done.
If I remove the cover on the aft side of the heater core, is there any room to snake my hand over to the panel door area?
How about from underneath if I remove the floor duct?
Been doing some professional grade pondering and have a PlanDuJour(tm), subject to change, as always.
The duct feeding the panel vents is split in two sections. If I remove three screws, the right side will be loose. I doubt I can remove it completely, but I just need to pull it aft and up a couple of inches. Then I can get in there with a pancake drill and remove those two rivets on the lower part of the hinge. I should be able to get the two bolts at the top with a ratcheting dogbone. Once I repair the hinge or fabricate something better, I will reinstall the door assembly with four bolts and no rivets.
Still hatching a scheme on how to reinstall the pin for the actuator end, on the inside of the door. That's why I'm wondering what sort of access is available via the heater core cover or the opening to the floor duct. I expect it the whole process will be like building a ship in a bottle, but I bet it can be done.