A/C vacuum diagram needed
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Elder User
Joined: May 2004
Posts: 836
Likes: 2
From: Shreveport, LA
A/C vacuum diagram needed
So I made an appeal over in the heating and air conditioning section and never really got anything useful.
I know some guys here have some pretty good shop manuals, though! Can someone give me guidance on how the AC vacuum system is routed for my 79 Bronco?
I figured I could find out myself using my little vacuum pump and I was making good progress, 'till I realized I'm not 100% sure which hose(s) are supposed to actually go to the vacuum source.
It appears that I have the factory hoses in the controller I have, so using color codes shouldn't be a problem, but the more information, the better!
I know some guys here have some pretty good shop manuals, though! Can someone give me guidance on how the AC vacuum system is routed for my 79 Bronco?
I figured I could find out myself using my little vacuum pump and I was making good progress, 'till I realized I'm not 100% sure which hose(s) are supposed to actually go to the vacuum source.
It appears that I have the factory hoses in the controller I have, so using color codes shouldn't be a problem, but the more information, the better!
Hotshot
Joined: Apr 2009
Posts: 14,333
Likes: 247
From: Stanley, VA
Okay, the small line with the brown stripe goes through the firewall to the water shut off valve in the heater hose.
The large diameter black hose goes through the firewall to the vacuum reservoir on the driver's side splash pan.
There are three vacuum servos, one near the passenger side kick panel and two up under the dash, over the transmission tunnel. One is silver colored the other kinda gold colored.
The hose with the yellow stripe goes in the end of the gold servo, the hose with the red stripe goes in the side.
The hose with the orange stripe goes in the end of the silver servo and the hose with the blue stripe goes to the side.
The hose with the white stripe goes to the servo by the passenger side kick panel.
The hose with the green stripe jumps between the upper and lower vacuum switches on the control panel......I think that's all of them.
The large diameter black hose goes through the firewall to the vacuum reservoir on the driver's side splash pan.
There are three vacuum servos, one near the passenger side kick panel and two up under the dash, over the transmission tunnel. One is silver colored the other kinda gold colored.
The hose with the yellow stripe goes in the end of the gold servo, the hose with the red stripe goes in the side.
The hose with the orange stripe goes in the end of the silver servo and the hose with the blue stripe goes to the side.
The hose with the white stripe goes to the servo by the passenger side kick panel.
The hose with the green stripe jumps between the upper and lower vacuum switches on the control panel......I think that's all of them.
Mountain Pass
Joined: Mar 2022
Posts: 114
Likes: 11
From: Mendocino county Califor
I don't have any vaccum operated flaps I have the incab high output heater and dealer installed economy ac. My question is related to vacuum as I have a vacuum can on the drivers side that is under the fender. It has one line goin towards the firewall running the length of the firewall to a check valve and splitter. Two vacuum lines go from there one goes to the amplifier and the other I guessed goes to the vacuum port under the egr because of length and bend. Any one actually know what I am supposed to run them to and also what is the vacuum for as I have no flaps that are vacuum controlled or vacuum ports on my ac control **** switch. Short of demanding more vacuum I dont see how or what the vacuum is for or accomplishing unless another line is going somewhere form the vaccum can. I still need to pull down the fender liner to see if that's the case.
Lead Driver
Joined: Jul 2017
Posts: 9,616
Likes: 1,182
From: San Jose, CA
I thought they left the vacuum canisters off in vehicles that did not need them, but perhaps they were simply installed on all trucks and you just have one that's plumbed in, but does not do anything?
You would still have the heater control vacuum valve though, correct? Would not the controls on the dash still utilize that? Or were they mechanical valves in the heater hose for trucks like yours.
Anyway, back to the top for someone with more knowledge to see again.
Good luck.
Oh, by the way, i don't suppose you still have the factory hose routing decals on the underside of your hood by any chance. Do you?
paul
You would still have the heater control vacuum valve though, correct? Would not the controls on the dash still utilize that? Or were they mechanical valves in the heater hose for trucks like yours.
Anyway, back to the top for someone with more knowledge to see again.
Good luck.
Oh, by the way, i don't suppose you still have the factory hose routing decals on the underside of your hood by any chance. Do you?
paul
Mountain Pass
Joined: Mar 2022
Posts: 114
Likes: 11
From: Mendocino county Califor
I thought they left the vacuum canisters off in vehicles that did not need them, but perhaps they were simply installed on all trucks and you just have one that's plumbed in, but does not do anything?
You would still have the heater control vacuum valve though, correct? Would not the controls on the dash still utilize that? Or were they mechanical valves in the heater hose for trucks like yours.
Anyway, back to the top for someone with more knowledge to see again.
Good luck.
Oh, by the way, i don't suppose you still have the factory hose routing decals on the underside of your hood by any chance. Do you?
paul
You would still have the heater control vacuum valve though, correct? Would not the controls on the dash still utilize that? Or were they mechanical valves in the heater hose for trucks like yours.
Anyway, back to the top for someone with more knowledge to see again.
Good luck.
Oh, by the way, i don't suppose you still have the factory hose routing decals on the underside of your hood by any chance. Do you?
paul
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Mountain Pass
Joined: Mar 2022
Posts: 114
Likes: 11
From: Mendocino county Califor
Looking at https://www.ford-trucks.com/forums/1...ngs-for-2.html it looks like it's for cruise control and my truck didnt come with cruise. So its just capped off. Strange but looks like they were making ordered options easy to install for the factory dealer and diy
I have cable driven flaps and dealer installed economy ac with not one vacuum port.
I have cable driven flaps and dealer installed economy ac with not one vacuum port.
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Mountain Pass
Joined: Mar 2022
Posts: 114
Likes: 11
From: Mendocino county Califor
do you just want a off valve or a cable driven valve? I'm thinking about finding a newer valve and see if I can re purpose it.
Mountain Pass
Joined: Mar 2022
Posts: 114
Likes: 11
From: Mendocino county Califor
cable driven
NewYall HVAC Heater Control Valve
vaccum driven
ACDelco Professional 15-5812 Heater Control Valve
Mountain Pass
Joined: Mar 2022
Posts: 114
Likes: 11
From: Mendocino county Califor
any of them you think you can install. Cable only needs a cable to open or close. The electric needs a button (I'm thinking of adding it to the dash with a indicator saying ac on when closed so I would have a way to know on or off) and vaccum needs a source of vacuum only to turn it off that may be more difficult especially without vacuum actuated flaps for hvac. All I showed have 3/4 inch connections. It's up to you how you want your truck but each would work. I have even see hose spigots on a heater core ( diesels usually have the hose connector on so you can swap coolant and warm up a engine without starting it) to even just a ball valve with a manual shut off like on a house
2nd Gear
Joined: Sep 2023
Posts: 2
Likes: 0
VACUUM HELP PLEASE
Okay, the small line with the brown stripe goes through the firewall to the water shut off valve in the heater hose.
The large diameter black hose goes through the firewall to the vacuum reservoir on the driver's side splash pan.
There are three vacuum servos, one near the passenger side kick panel and two up under the dash, over the transmission tunnel. One is silver colored the other kinda gold colored.
The hose with the yellow stripe goes in the end of the gold servo, the hose with the red stripe goes in the side.
The hose with the orange stripe goes in the end of the silver servo and the hose with the blue stripe goes to the side.
The hose with the white stripe goes to the servo by the passenger side kick panel.
The hose with the green stripe jumps between the upper and lower vacuum switches on the control panel......I think that's all of them.
The large diameter black hose goes through the firewall to the vacuum reservoir on the driver's side splash pan.
There are three vacuum servos, one near the passenger side kick panel and two up under the dash, over the transmission tunnel. One is silver colored the other kinda gold colored.
The hose with the yellow stripe goes in the end of the gold servo, the hose with the red stripe goes in the side.
The hose with the orange stripe goes in the end of the silver servo and the hose with the blue stripe goes to the side.
The hose with the white stripe goes to the servo by the passenger side kick panel.
The hose with the green stripe jumps between the upper and lower vacuum switches on the control panel......I think that's all of them.
THANKS SO MUCH
2nd Gear
Joined: Sep 2023
Posts: 2
Likes: 0
CONTROL BULK HEADS
Okay, the small line with the brown stripe goes through the firewall to the water shut off valve in the heater hose.
The large diameter black hose goes through the firewall to the vacuum reservoir on the driver's side splash pan.
There are three vacuum servos, one near the passenger side kick panel and two up under the dash, over the transmission tunnel. One is silver colored the other kinda gold colored.
The hose with the yellow stripe goes in the end of the gold servo, the hose with the red stripe goes in the side.
The hose with the orange stripe goes in the end of the silver servo and the hose with the blue stripe goes to the side.
The hose with the white stripe goes to the servo by the passenger side kick panel.
The hose with the green stripe jumps between the upper and lower vacuum switches on the control panel......I think that's all of them.
The large diameter black hose goes through the firewall to the vacuum reservoir on the driver's side splash pan.
There are three vacuum servos, one near the passenger side kick panel and two up under the dash, over the transmission tunnel. One is silver colored the other kinda gold colored.
The hose with the yellow stripe goes in the end of the gold servo, the hose with the red stripe goes in the side.
The hose with the orange stripe goes in the end of the silver servo and the hose with the blue stripe goes to the side.
The hose with the white stripe goes to the servo by the passenger side kick panel.
The hose with the green stripe jumps between the upper and lower vacuum switches on the control panel......I think that's all of them.
THIS HELPS ON 1974 F100 AC CONTROLS