Hidden Heater Control Valve

[Speedrdr]

Reread Steve83’s post. Oopsie! Must have scanned right over the part about it had an AC attached. I’m just in too big of a hurry reading.
Sorry.

Randy

 

[bigmuddy]

Nope. All the same. Probably even '66, but I can't promise anything with a '66!

Don't remember anyone saying you had to replace the whole box. Just when updating to aftermarket A/C as it's currently made would be the only reason i can think of. Even an old busted up plenum can be replaced with new parts these days.
Reasons for taking the whole thing apart might be to fix cracks, insulate the interior and exterior to reduce noise and errant heat when you don't want it. And maybe to paint the exterior.
Otherwise, the core and the seals are the only common thread from years past to now.

And yes to simply adjusting everything to your satisfaction using one, two or three of the control knobs.

Paul

So yes you are wrong and yes you are right, jeezle...

In the end, I can't explain Fords ideas on the heater design any better than why they now support some social causes of the day, but I digress!
DirtDonk said it best I think: It's as simple as you can push, pull or twist all three knobs until you are satisfied with the amount of heat that you need or don't!

 

[MarsChariot]

But only sometimes…

there, you just said it wrong again.
Maybe….
The pull for heat is not opening a valve. At least not the heater control valve under the hood.
It is opening and closing a damper door only.
It does not increase or decrease the flow of hot water from the engine.
That is solely the job of the heater control valve under the hood.
Which is controlled by the TEMP knob.

What I said: ...The center knob controls the flap. The right knob modulates the valve controlling the water flow.

 

[TDubya]

As I read through this thread, I think some of the confusion is that the diagram that Steve83 provides seems to be incorrect. It shows the center knob for fan/pull for heat connecting to the valve in the heater hose and the left knob connecting to the flap. Unless I'm reading the diagram wrong... And as I look at it again, the diagram is correct, its just that the knobs aren't oriented from left to right as they are on the dash

 

[Steve83]

...unfiltered, unconditioned air flowing...

Your Bronco has a cabin air filter? Or factory A/C?

...not that a leaky Bronco would seal it all out...
With the hard top on, there's not much flow inside a Bronco's interior.

Except for all the leaks.

...not manually accessible from the driver's seat while driving.

Compared to all the leaks, that little flap isn't significant. And the issue is what difference the flap makes when CLOSED. If it wasn't there (as I expect since it's useless), it would be the same as always open. The only question is why CLOSE it? It won't really stop or even slow the airflow through the cabin due to all the leaks; stopped or at highway speed; hot or cold.

...the diagram is correct, its just that the knobs aren't oriented from left to right as they are on the dash

Which diagram? I've posted a few, and I think they all show the same order for the knobs: Defrost, Heater/Fan, Temp. What order do you think is correct?

(click this text)


Look at the far right side of this diagram:

(click this text)

 

[DirtDonk]

Your Bronco has a cabin air filter? Or factory A/C?

Nope. Just commenting that Broncos don’t have such a thing, such as a modern vehicle has.
Just air coming from the outside into the heater plenum. The only conditioning is the heat coming from the core.

Compared to all the leaks, that little flap isn't significant. And the issue is what difference the flap makes when CLOSED. If it wasn't there (as I expect since it's useless), it would be the same as always open. The only question is why CLOSE it? It won't really stop or even slow the airflow through the cabin due to all the leaks; stopped or at highway speed; hot or cold.

I disagree. While it’s not excessively efficient, opening and closing the flap at the drivers left foot does indeed introduce outside air that you can feel. Same as pulling the “pull for heat“ knob on the dash gives you air out of the heater duct that you can feel.

Sometimes you just don’t want to open the windows much if you can avoid it.

 

[TDubya]

Your Bronco has a cabin air filter? Or factory A/C?

Except for all the leaks.

Compared to all the leaks, that little flap isn't significant. And the issue is what difference the flap makes when CLOSED. If it wasn't there (as I expect since it's useless), it would be the same as always open. The only question is why CLOSE it? It won't really stop or even slow the airflow through the cabin due to all the leaks; stopped or at highway speed; hot or cold.

Which diagram? I've posted a few, and I think they all show the same order for the knobs: Defrost, Heater/Fan, Temp. What order do you think is correct?

(click this text)


Look at the far right side of this diagram:

(click this text)

I was referring to the exploded view diagram which at first glance appears to have the knobs oriented from left to right: Heater/Fan, Temp, Defrost.