Long story short, working on getting A/C and vents going, the dash controls dont seem to be working, all the vacuum lines seem to be okay but I noticed an absent "nipple" on the back of the control module where the rest of the lines were connected. I thought maybe this could be the supply line for the vacuum. Where, under the hood, is the source for the vacuum? What am I looking for? Thanks a ton!
CK5
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vacuum supply line for dash
- Thread starter solace22
- Start date
I think the line comes from a cannonball looking vacuum reserve tank on the firewall,which gets its vacuum from the intake manifold..
I checked that ball and it has one small line that goes to nothing coming off it and thats its.
However, I did figure it out. It really helps to have engine vacuum when the engine is running. Im crazy.
But it is weird that nothing is connected to that cannonball looking item. Should there be something?
It looked like there was a T connector off an intake tube that supplied the vacuum and it had a small T on it that had a very tiny orange/black line that was connected to nothing. I presumed it went somewhere on the air cleaner.
However, I did figure it out. It really helps to have engine vacuum when the engine is running. Im crazy.
But it is weird that nothing is connected to that cannonball looking item. Should there be something?
It looked like there was a T connector off an intake tube that supplied the vacuum and it had a small T on it that had a very tiny orange/black line that was connected to nothing. I presumed it went somewhere on the air cleaner.
Last edited:
454Sub
5/8 ton status
If memory serves there is a one way check valve/T thing between the intake and cab. It is positioned (again if memory serves) so that the ball retains full vacuum all the time and is just released when a AC panel control is moved. Other than that the vacuum never fluctuates in the pod. The T thing obviously has 3 ports. So the two that are "connected" inside that T thing go to the cab and the ball, the other end goes to full intake vacuum. Regardless of how high or low the engine is running that ball should retain a steady high vacuum situation inside it. Until the AC controls are moved and it releases it to move whatnot around.
It would help to know what year your truck is. I think they changed from gen 1 to gen 2. I only can tell you from experience with my gen 2 (1975). On my truck, there is a 1/4" vacuum line coming off the intake manifold that goes directly to the large port on the vacuum canister. My vacuum canister, which I believe is OE, has a built in check valve. In the direct center of the vacuum canister, there is a much smaller vacuum nipple that connects a gray 1/8" vacuum line that goes into the firewall. This gray line supplies vacuum to run the entire AC system.
