# 66 gto ac vacuum line diagram needed



## azaapcom (Jul 1, 2010)

help i need a diagram of the vacuum lines for the air con , i didnot take the car appart so i dont know where any of the hoses go any help would be great thanks:confused


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## azaapcom (Jul 1, 2010)

please can anybody help me with this , i need to put the vacuum hoses back so i can fit the dash , any help would be great thanks


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## Eric Animal (Oct 28, 2007)

From the service manual for 1967, but I am almost sure 66 is the same.The small "round wheel" in the lower left corner is the dash control. The vacuum ports are numbered. Eric


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## azaapcom (Jul 1, 2010)

thank you mr animal that is very helpfull , please check out my web site www.azaap.com if you need any rust free arizona parts also some pics of the gto i am doing $25 hour shop rates for restorations , my wife will up date the web pictures on sunday so you can see all my pontiacs mostly ta,s:cheers


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## Eric Animal (Oct 28, 2007)

MY pleasure. I could use a rust free 67 GTO shell......Cool pygmy goats and nice puppies ! Eric:cheers heres's a couple of my "critters"


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## CPL (Feb 11, 2016)

I have a 65 this looks the same,except for were the lines connect at the junction to go out to the engine.is that a canister or a junction into one line to engine?
thanks


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## GTOJUNIOR (Aug 7, 2011)

If your referring to round/circle portion of the schematic, if you look close you will note there are numbers.
That circular image represents the Vacuum Valve/Control head.

Similar to this;


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## CPL (Feb 11, 2016)

My vacuum lines go threw the fire wall I don’t have that pice.at some point who ever had my car first cut the vacuum lines coming out into the engine compartment.the scamatic looks the same until you get to that vacuum valve.


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## Andrew69 (Dec 28, 2017)

This is good information but does anyone have a schematic of the vacuum lines as they route into and through the engine bay?

Thank you,
Andrew


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## Andrew69 (Dec 28, 2017)

To be more specific I need to know how to route the 1/8" vacuum lines that come through the firewall in the upper part of the heater box. Anybody have a similar car that you can send me some photos?

Attached is a photo I found on line to clarify which lines.

Thank you,
Andrew


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## Andrew69 (Dec 28, 2017)

Bumping this back to the top with hopes of getting some help. 

Is this vac canister the correct type for a '67 model? https://www.opgi.com/gto/GBC0592/ 
Or is it this? https://www.npdlink.com/store/?p=catalog&mode=newsearch&search_str=c-9196-10a&parent=10000&year=1967 

If either one where does it mount? How do the hoses route to and from it?

Thank you,
Andrew


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## JNYBOY (Sep 28, 2017)

Andrew69 said:


> To be more specific I need to know how to route the 1/8" vacuum lines that come through the firewall in the upper part of the heater box. Anybody have a similar car that you can send me some photos?
> 
> Attached is a photo I found on line to clarify which lines.
> 
> ...


Not sure if this helps, but these are pics from my 66'....Everything (AC/Heater ) works !


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## Andrew69 (Dec 28, 2017)

Thank you very much JNYBOY. On yours as well as others I see have two hoses going to the vacuum actuator. This car has the vacuum actuator but with only one inlet. I am beginning to believe this car has an incorrect vacuum actuator.

What says the GTO Hive?


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## GTOJUNIOR (Aug 7, 2011)

That is without question the wrong actuator. All '66 AC equipped A-Bodies utilized the plastic two port unit.
These are avail from most major Pontiac vendors, However the air box/case will need to be removed for installation.

Attached below are the Vacuum Diagrams from the 1966 Tempest Air Conditioning Manual.
If I can can assist further with anything from the manual just let me know.
Cheers


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## JNYBOY (Sep 28, 2017)

....I agree with GTOJUNIOR, that the one in your picture is incorrect. ...I looked up the correct one for the 66', in the Original Parts Group Catalogue and it's Part # BR02521...$88.00...Maybe a better price somewhere else, but ....... My Best J


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## Andrew69 (Dec 28, 2017)

GTOJUNIOR said:


> That is without question the wrong actuator. All '66 AC equipped A-Bodies utilized the plastic two port unit.
> These are avail from most major Pontiac vendors, However the air box/case will need to be removed for installation.
> 
> Attached below are the Vacuum Diagrams from the 1966 Tempest Air Conditioning Manual.
> ...


Thanks for the info, pictures and drawings. On these cars does removal of the air box/case include removal of the fender like my '69 Camaro?



JNYBOY said:


> ....I agree with GTOJUNIOR, that the one in your picture is incorrect. ...I looked up the correct one for the 66', in the Original Parts Group Catalogue and it's Part # BR02521...$88.00...Maybe a better price somewhere else, but ....... My Best J


I'm working on a '67 model and see it is represented for '65 - '67. https://www.opgi.com/gto/1967/interior-accessories/heater-ac/BR02521/ I'll have to place my order.

Thanks again,
Andrew


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## GTOJUNIOR (Aug 7, 2011)

Sorry Andrew I saw the heading for '66 didn't take note your working on a '67.
All info; still applies. 

AMES PERFORMANCE;


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## Andrew69 (Dec 28, 2017)

I guess I should not have hijacked another thread but the topic is similar. I am working on a '67 model and do appreciate the help.

So, do I have to remove the passenger fender? I hope not.

A photo for your viewing pleasure. :smile3:


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## JNYBOY (Sep 28, 2017)

...OooEeee !...A Real Sweetie you have there...Good Luck on the Project !


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## GTOJUNIOR (Aug 7, 2011)

I had to go look at the '66 it's the only one with AC. 
It's been awhile and the more I thought about it I had to go look and have to retract the statement on removing the Plenum.

You can access the speed nuts on the actuator by removing the interior main ducting, this will reveal the opening/access into the Plenum from the interior.
Its tight but can be done. It may require removing the Radio for better clearance/access but you'll be able to determine that once you have the duct out.
Below is a shot of a loose plenum showing the location of the opening on the plenum. 
FWIW the smaller image I just shot with my Iphone scope I probed up/under the dash showing the speed nuts and arm screw that retain the vacuum actuator.

Side Bar;
I maintain a twin to your '67 for a sweet older lady.
Luckily it's Non AC 

Cheers


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## Andrew69 (Dec 28, 2017)

Thanks for the photos GTO Jr. Because I am also cleaning up the rat nest of wiring under the dash I have the radio, ductwork and glove box removed already. I can see inside the plenum and see the actuator but cannot get my hands in there. Just what does this actuator actuate?

I removed all the nuts holding on the plenum including those on the bottom that required Cirque de Solel grade contorting, removing some inner fender bolts, swivel sockets and ratchet wrenches. This thing was glued in place with some black silicone stuff and while I can pull it off the firewall it seems to be held back by something. Perhaps the ductwork that goes into the fender. When I can get back out there I may try removing more inner fender bolts to see what is holding it back. When I reassemble should I use some dumdum type sealant? I used black silicone on my Camaro but looking back maybe I should not have.

This is a nice car belonging to a colleague at work. I agreed to work on it and he agreed to pay me for my efforts. It is a older restoration with dried seals, belts and holes, heat didn't work, AC doesn't work and various other ailments. I'm having fun and making a few bucks but this thing is whooping me.

My old car is a '69 Camaro I built twelve years ago. Some photos on the sister site. Team Camaro Showroom - Andrew69 Gallery 

Thanks again for your help.

Andrew


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## GTOJUNIOR (Aug 7, 2011)

Yes the plenum is sealed very well from the factory and will require a lot of effort to release.
You shouldn't have to touch the fender if you remove the duct between the Evaporator & Plenum cases.
This is also sealed at each end so go slow as I'm not sure this is avail. 
Once off it will reveal a bolt if you already haven't seen it.

IIRC the actuator your after controls the inlet vent. 
The single port actuator in that location now is similar if not exactly like the one mounted on the interior side used to control the defrost door.

Once your at the point of re-installation 3M Strip caulk is a great choice for sealing things such as this.


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## Andrew69 (Dec 28, 2017)

That duct you mention I have the screws removed from the top but didn't see those on the bottom. I'll remove them too and then this thing should pull straight off. I did remove that hidden nut you identified. Today I see this duct has screws inside the fender area that I cannot easily reach. Wish the fender well was removable without messing with the fender.

This has been off before based on the excessive sealant across the top edge and mismatched small screws on the upper half of the duct. The upper screws on the plenum don't seem to be gripping any metal. Either they were stripped out or the screws used are too small. From memory they are 5/16" sheet metal screws. What is correct? If 5/16" I may back the metal with something to grip or might use 3/8" screws.

With the help of both of you my confidence is restored. I hope once I get the under dash wiring straightened up and this plenum corrected he will have both heat and AC. I found he had no heat because a connector on the sliding switches was incorrectly connected and it blew the heat fuse every time you turned it on. I figured while I have the fan motor out I might change it out too.

Oh, and even though things are tight I am glad I don't have to remove the fender.

Thank you.


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## cij911 (Oct 25, 2017)

Sorry for the noob question, but why in the world would vacuum lines be used with the HVAC system ? I am sure my 65' convertible doesn't have this....What am I missing ??? Thanks


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## Andrew69 (Dec 28, 2017)

The vacuum is used to open and close doors in the air ducts to direct to floor, forward or defrost. Your car might use cables to do the same, but I don't know the '65 models.


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## Andrew69 (Dec 28, 2017)

I have a spare bulb and wire.

The blue wire seems to route to the oil filter. Where does it plug in?

The lamp and socket is on LH side with no obvious place to plug it? Brown and pink wiring. Where does it go?


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## GTOJUNIOR (Aug 7, 2011)

Something seems to be amiss, The Pink/Brown lamp is ammeter, which indicates you have standard gauges Vs rally.
The odd thing is the Dark blue lead connector end isn't correct for lights(standard Gauges) ?? but should be oil PSI related.


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## Andrew69 (Dec 28, 2017)

This is the dash in this car. I have no idea what a previous owner might have done. I imagine this the standard gauge package considering the lack of tachometer.

Update: Yesterday I pulled the dash carrier back looking for the elusive socket to plug that lamp. It turns on with the oil pressure idiot light when I turn the key to the first stop position so it is warning light related. For now I will remove the bulb and tie it out of the way in an accessible location.
The blue wire seems like it should plug into a spade on the back of a gauge. Like the lamp I cannot fine a logical place to plug it. So for now will leave it unplugged.
What I don't know is if someone in the past made changes to the dash gauges without updating the wiring.
If anyone has any better ideas please jump in.


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## Andrew69 (Dec 28, 2017)

Update: I absolutely could not get the heater box out so the fender came off. Now that I could see behind it I found the clamp screw for the upper heater hose was blocking the unit from pulling away. :-(

I now have it apart and will order the new actuator but first this needs cleaning and painting. Anyone know where I can get the plug thingy for the 3 hoses and wiring pass through?

What is the correct color of black for the heater box? Gloss black or semi flat?


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## Andrew69 (Dec 28, 2017)

The blue wire pictured above does not go to above the oil filter but instead disappears behind the firewall padding routed towards the floor. I applied power to see if anything happens with no obvious results. Removed the door sill and pulled up the carpet and didn't spot it. Still puzzled. Maybe it is a rogue wire someone added that is no longer utilized.


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## Andrew69 (Dec 28, 2017)

On the photo posted on page one it seems the plenum has a cut gasket. Is this available somewhere?

Edit: With a little searching it seems the answer is yes: https://www.opgi.com/gto/CH17364/


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## Andrew69 (Dec 28, 2017)

Today I am to the point of figuring out which vacuum hose goes where. The upper slide has these markings:

DE-ICE HEAT OFF VENT OUT INSIDE

DE-ICE - LH actuator pulls defrost door to direct air to the windshield
HEAT - LH Actuator releases to allow air to floor
Off - No vacuum to anywhere (Correct?)
VENT - Air inlet pulled open and Diverter Door open to circulate into cabin
OUT - AC on with fresh air (Air inlet open)
INSIDE - AC on with recirculate (Air inlet closed)

I routed the lines based on the attached diagram. I find the firewall mounted actuator does not release whenhe slide is set to INSIDE. I can also hear a leak when slide is set to OUT. Because I am testing with a hand pumped vacuum it is difficult to find the leak.

I need to know which of these go where and the possibility of the slide valves needing repair or replacement. Is this manifold numbered counterclockwise beginning at the 5:00 position?

Am I making any sense?


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## Andrew69 (Dec 28, 2017)

For the benefit of someone else with the same question:

Using my Mityvac to pull a vacuum I tested all options of vacuum draw and which ports are open when the climate selectors are made. It seems the chart is correct as long as you follow the numbering on the manifold, which is numbered clockwise. You cannot see it unless you remove it from the dash.

Port Application
1 Actuator on firewall primary line
2 Actuator on firewall secondary line
3 Manifold vacuum
4 Actuator to direct air to defrost
5 Actuator to direct air through AC ducts


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## betatronix (Apr 7, 2021)

azaapcom said:


> help i need a diagram of the vacuum lines for the air con , i didnot take the car appart so i dont know where any of the hoses go any help would be great thanks:confused


Hello please, Can someone help me, I am connecting the air conditioning of a 1966 Pontiac GTO and I do not know where it is connected what is underlined in the image,


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## betatronix (Apr 7, 2021)

azaapcom said:


> help i need a diagram of the vacuum lines for the air con , i didnot take the car appart so i dont know where any of the hoses go any help would be great thanks:confused


Hello please, Can someone help me, I am connecting the air conditioning of a 1966 Pontiac GTO and I do not know where it is connected what is underlined in the image,


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## GTOJUNIOR (Aug 7, 2011)

It is an inline CHECK VALVE;


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