AC/Heater Control Vacuum Valve
12-02-2014, 06:11 PM
#1
Racer
Thread Starter
AC/Heater Control Vacuum Valve
The 9-port valve that's inside the console.
Before I trace out every function of this valve, has anyone done this before? I'm still restoring my '72 454 AC and have the ductwork installed at this point, and everything has been rebuilt except the console control panel. What I'd like to do is test all the valve position functions to make sure everything works as it should. IE, what should happen (opens, closes) when "Vent" is selected, etc., etc.
I ran through a few tests while hooked up to a vacuum pump, and some things didn't add up. In my mind, anyway. I'm thinking I either have a leaky control valve or the control panel wheel is messed up.
The valve has two ports that are plugged (4 & 7), and one that is open but plugged (2?) via the rubber quick connector. I won't be using that quick connector, and just plugging the hoses directly into the various ports.
If anyone out there has already been through this, I'd like to hear from you! All help appreciated!
Before I trace out every function of this valve, has anyone done this before? I'm still restoring my '72 454 AC and have the ductwork installed at this point, and everything has been rebuilt except the console control panel. What I'd like to do is test all the valve position functions to make sure everything works as it should. IE, what should happen (opens, closes) when "Vent" is selected, etc., etc.
I ran through a few tests while hooked up to a vacuum pump, and some things didn't add up. In my mind, anyway. I'm thinking I either have a leaky control valve or the control panel wheel is messed up.
The valve has two ports that are plugged (4 & 7), and one that is open but plugged (2?) via the rubber quick connector. I won't be using that quick connector, and just plugging the hoses directly into the various ports.
If anyone out there has already been through this, I'd like to hear from you! All help appreciated!
12-02-2014, 06:19 PM
#2
Drifting
You need the Helm Shop Manual or AIM for your specific year car to trace these properly- It seems GM made subtle changes to these vacuum systems almost every year.
The Shop Manual / AIM will have a chart that shows which ports should have vacuum based on each control setting.
The Shop Manual / AIM will have a chart that shows which ports should have vacuum based on each control setting.
12-02-2014, 06:38 PM
#3
Racer
Thread Starter
You need the Helm Shop Manual or AIM for your specific year car to trace these properly- It seems GM made subtle changes to these vacuum systems almost every year.
The Shop Manual / AIM will have a chart that shows which ports should have vacuum based on each control setting.
The Shop Manual / AIM will have a chart that shows which ports should have vacuum based on each control setting.
I'd still like to hear of other's experiences with this, such as how to test the valve for proper function or leaks. Is it vacuum 'black' with only a single port active with each rotation and all other ports blocked or are there combo ports open to vacuum while in certain positions. Kind of thing.
12-02-2014, 07:17 PM
#4
Le Mans Master
Member Since: Aug 2006
Location: mount holly NC
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C3 of Year Finalist (appearance mods) 2019
In Color!
Willcox has a color diagram if you have A/C.
How I think it works:
When system is on HEAT or NORMAL A/C the top valve is open to let outside air into the system and the bottom (kick pad) is closed.
When A/C is on MAX the TOP valve is CLOSED and kickpad valve is open.
Inside air is drawn in through the kick pad.
Port # 1 green hose-outside air.
Going clockwise from there:
#3 black-vacuum supply
#5 pink -heater
#6 red -de ice
#8 tan -AC
#9 blue-defog
How I think it works:
When system is on HEAT or NORMAL A/C the top valve is open to let outside air into the system and the bottom (kick pad) is closed.
When A/C is on MAX the TOP valve is CLOSED and kickpad valve is open.
Inside air is drawn in through the kick pad.
Port # 1 green hose-outside air.
Going clockwise from there:
#3 black-vacuum supply
#5 pink -heater
#6 red -de ice
#8 tan -AC
#9 blue-defog
Last edited by Peterbuilt; 12-03-2014 at 03:10 PM.
12-08-2014, 04:01 PM
#7
Racer
Thread Starter
12-19-2014, 07:05 PM
#8
AC/Htg vacuum chart
Willcox has a color diagram if you have A/C.
How I think it works:
When system is on HEAT or NORMAL A/C the top valve is open to let outside air into the system and the bottom (kick pad) is closed.
When A/C is on MAX the TOP valve is CLOSED and kickpad valve is open.
Inside air is drawn in through the kick pad.
Port # 1 green hose-outside air.
Going clockwise from there:
#3 black-vacuum supply
#5 pink -heater
#6 red -de ice
#8 tan -AC
#9 blue-defog
How I think it works:
When system is on HEAT or NORMAL A/C the top valve is open to let outside air into the system and the bottom (kick pad) is closed.
When A/C is on MAX the TOP valve is CLOSED and kickpad valve is open.
Inside air is drawn in through the kick pad.
Port # 1 green hose-outside air.
Going clockwise from there:
#3 black-vacuum supply
#5 pink -heater
#6 red -de ice
#8 tan -AC
#9 blue-defog
12-20-2014, 11:52 AM
#11
Former Vendor
Member Since: Aug 2006
Location: Jeffersonville Indiana 812-288-7103
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St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
12-21-2014, 12:51 AM
#13
Former Vendor
Member Since: Aug 2006
Location: Jeffersonville Indiana 812-288-7103
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St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
My pleasure Tommy..
Willcox
Willcox