Hvac vacuum lines?

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PJNJ201

Not-quite-so-new-guy
Feb 9, 2021
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Hey guys. trying to figure out where certain vacuum lines go from the twinkie style vacuum tank by the blower motor. car is an 84 buick regal.

As pictured below, the line with the red and black braded sleeve that IS connected is a gray line. the nipple on there that has nothing connected, there was a black line that was just laying there tucked away so i took it off for now. Also as pictured, there is a tannish line that is also just hanging there tucked away. Currently all i have is defrost and vent and high speed does not work. Thanks all!
 

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mikester

Comic Book Super Hero
Mar 10, 2010
2,904
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Small town NY
On my car theres a purple line coming from the firewall going to the vacuum ball. That might be the gray line on your car just faded. The tan line goes to the valve in the heater hose. Then you will have a line feeding the ball or tank coming from the manifold providing vacuum.
IMG_0019.jpg
 
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PJNJ201

Not-quite-so-new-guy
Feb 9, 2021
46
55
18
On my car theres a purple line coming from the firewall going to the vacuum ball. That might be the gray line on your car just faded. The tan line goes to the valve in the heater hose. Then you will have a line feeding the ball or tank coming from the manifold providing vacuum.
View attachment 195628
Thanks for the info! I dont have a valve in my heater hose 🤔 is there a specific part number? how does it go in there? & also, im out of sources for vacuum. What is best to tee into for the vacuum?
 

mikester

Comic Book Super Hero
Mar 10, 2010
2,904
3,641
113
Small town NY
Thanks for the info! I dont have a valve in my heater hose 🤔 is there a specific part number? how does it go in there? & also, im out of sources for vacuum. What is best to tee into for the vacuum?
Not sure what ports are on a Buick. The 350 has a threaded hole on the back of the manifold. I put a T in the line going to the trans modulator.
 
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350Regal

Apprentice
Feb 23, 2022
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75
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On my car theres a purple line coming from the firewall going to the vacuum ball. That might be the gray line on your car just faded. The tan line goes to the valve in the heater hose. Then you will have a line feeding the ball or tank coming from the manifold providing vacuum.
View attachment 195628
I know this is off topic.. but...damn that engine bay I only see a part of it it looks very nice. Josh
 
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57 Handyman

Master Mechanic
Feb 6, 2017
338
388
63
PJNJ, the fan speed issue is probably caused by a bad fan resistor which sits on top of AC box. With regard to the vacuum lines and breadbox tank, there probably IS a leak that prevents the HVAC actuator from directing airflow between floor and defrost. The box in my 87 El Camino leaked so I replaced it with a small vacuum ball that is more readily available than the box. I suggest either borrowing a vacuum test kit from Autozone or purchasing one from Amazon. I opted to purchase one since it was around $25 or so and a great addition to my hobbyist toolbox. The vac pump tester is very helpful and key in troubleshooting your HVAC actuators, dash controls, plastic lines, etc.
 
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ELCAM

Royal Smart Person
Jun 19, 2021
1,116
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Hi speed is powered by the Hi speed relay all the lower speeds are powered through the resistor block. Make sure the orange wire from the HVAC controll has 12V present at the relay when the switch is in the hi setting.

Make sure there is 12V on the red 12Ga wire going into the relay.

If 12V is present in both cases the relay is defective.

FourSeasonAirConditioner (2).jpg
 
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