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Heater door won't close

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Old 06-14-2018, 04:33 PM
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cpep
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Default Heater door won't close

First a little quick history. I have a '73 Roadster w/air conditioning. Passenger side ALWAYS has hot air blowing to the feet. Running the air helps but suffice it to say it's not right. So I found this vacuum operated door was partially open. The door moves when going through the various heater control settings but will not close tight. AND (this is strange) when in air mode there is air blowing through this door opening BUT the fan switch is disconnected..I don;t know if it's by design to make sure air flows through the evaporator coils and if that is the case does the fan switch override something to change fan speeds? That I'm actually just curious about. The hot feet thing is what I really need help with.
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Old 06-14-2018, 07:19 PM
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DUB
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This door has a neutral position if my memory serves me correctly. So..the door will stay partially open.

The vacuum pod that moves this door has TWO vacuum hoses going to it and it will either suck the door closed or OPEN it all the way DEPENDING on the vacuum source that is being requested when you move your controls.

You can have a bad pod also.

You can possibly have a bad vacuum hose or vacuum supply.

Post #13 may interest you in the thread below...and this is the pod that moves this door if my memory serves me correctly.

https://www.corvetteforum.com/forums...d-problem.html

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Old 06-14-2018, 08:41 PM
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Originally Posted by DUB View Post
This door has a neutral position if my memory serves me correctly. So..the door will stay partially open.

The vacuum pod that moves this door has TWO vacuum hoses going to it and it will either suck the door closed or OPEN it all the way DEPENDING on the vacuum source that is being requested when you move your controls.

You can have a bad pod also.

You can possibly have a bad vacuum hose or vacuum supply.

Post #13 may interest you in the thread below...and this is the pod that moves this door if my memory serves me correctly.

https://www.corvetteforum.com/forums...d-problem.html

DUB
All great info thank you. The neutral position is interesting. It actually does look like it parks itself there for whatever the reason but it also has a sealing gasket so it must close too. That being said it opens when the air is on (moving towards engine) and comes back towards interior for everything else. Just not all the way. So one would think the second vacuum isn't doing its job. So we'll start there. Sound right?
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Old 06-15-2018, 08:57 AM
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derekderek
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You will always get heat unless you put REAL shutoff valve in 1 heater hose.
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Old 06-15-2018, 09:32 AM
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YES. That pod that I showed you a photo of can have that seal be bad...which would cause the pod not be able to close.

The reason the door works in the other direction is because the seal that I showed you is not being used and the diaphragm in the pod itself is and that is why it works.

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Old 06-15-2018, 01:28 PM
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cpep
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Originally Posted by derekderek View Post
You will always get heat unless you put REAL shutoff valve in 1 heater hose.
I'll keep that as an option. I'll just go into it a little more first. After all, I doubt a Chevy dealership would have said this is what we need to do to the original owner back in '73.
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Old 06-15-2018, 01:53 PM
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For what it is worth:

I service many Corvettes that are still factory original in design and they do not have any other hot water shut off valve installed. ...and the cars A/C will darn near freeze you out of the car. And yes...a thorough covering of the firewall and floorboards/transmission tunnel were covered in the DynaMat products also. Because I install two different layers of the DyanMat products.

Common sense would dictate that if you completely by-pass the hot water getting into your heater core...all you would be dealing with is the hot air from outside. But do not forget about the radiant heat from your exhaust that gets on the evaporator core case also.

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Old 06-22-2018, 08:50 PM
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Well I finally got back to looking at this today and here is the update. I put the mighty vac on all the hoses and they all hold a vacuum. So eliminated that. This door pulls just fine just won't push it closed. And it needs to close for the air to be directed towards the defroster vent. Which explains why that was so downright terrible on this car. Turns out the little plastic attachment thing was cracked at the bolt hole. So it lost its rigidity.


Here you can see the crack

So as long as it wasn't broke off completely here's my fix using a 3/8" conduit clamp.

I notched it to fit over the plastic piece.



So now the door closes. Almost. There's still a gap but it is tons better. In this picture it was already starting to move after shutting the car off so it really is a little tighter than what you see. Now on to the blower fan high speed not working.
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Old 06-23-2018, 10:02 AM
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GREAT INGENIUITY! But you are are w that Willcox sells that part new....not that it matters.

AS for the HIGH speed fan not working..If you get into a bind on it adn can not figure it out...let us know.

In most cases is it the connector at your blower relay has gone bad and got hot and the terminals are not gripping very well any longer and have gotten dirty.

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Old 06-23-2018, 03:18 PM
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I had spent some time looking for that part and came up empty.Not knowing what the part might be called (diverter door attachment thingy didn't do the trick) I lost patience and gave up early. I haven't used Willcox as a vender yet but definitely will do so in the future. And good call on the relay. The three wire connector is actually melted. What causes that? Relay bad?
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Old 06-23-2018, 06:21 PM
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The connector melted due to the amount of current that flows through that terminal when the blower mortar is on HIGH. The terminal is not protected from the weather elements... so over time it gets dirt, dust in there and it can cause the terminal to heat up becasue the terminal is not really gripping that well. It is perpetual cycle that will reach the point where the blower motor will not work on high..

The relay may be good..but the wire terminal may be dirty and tarnished and not able to grip well to make the blower work.

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