Vacuum Storage Canister
Le Mans Master
Joined: Oct 2010
Posts: 6,938
Likes: 848
From: melbourne florida
2023 C3 of the Year Finalist - Modified
When I bought my vette, the PO said the headlights would never go down... He spent $1000 bucks at a shop having them fixed up, and a month later they did the same thing... He called it the Achilles heel of the corevettes and I would grow to hate them... Lol
So, every time I turned off the lights I would hear a hiss under the dash... Figured it was a vacuum line that had unplugged or rotted out... Started to investigate the hiss under the dash and noticed that little plunger... Didn't know what it did at the time so I pushed it in, and saw the vacuum lines running to it ... Got a huge smile on my face, and fired up the car... Headlights worked flawlessly! Lol.
The PO was not mechanically inclined, and must've pulled the 'emergency vacuum release ' plunger down, and never pushed it back up... THATS all it took for me to get my lights to function properly... Lol.
So... Track down any vacuum leaks, properly hook up the canister, and see what results you get... Could be bubba just didn't understand the system and started unplugging things to get his lights to function properly with the car running... ;-)
So, every time I turned off the lights I would hear a hiss under the dash... Figured it was a vacuum line that had unplugged or rotted out... Started to investigate the hiss under the dash and noticed that little plunger... Didn't know what it did at the time so I pushed it in, and saw the vacuum lines running to it ... Got a huge smile on my face, and fired up the car... Headlights worked flawlessly! Lol.
The PO was not mechanically inclined, and must've pulled the 'emergency vacuum release ' plunger down, and never pushed it back up... THATS all it took for me to get my lights to function properly... Lol.
So... Track down any vacuum leaks, properly hook up the canister, and see what results you get... Could be bubba just didn't understand the system and started unplugging things to get his lights to function properly with the car running... ;-)
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
Worn seals in the headlamp relays are the usual cause of poor headlamp movement.
P.S. The vacuum reservoir maintains the vacuum level...whether engine is ON or OFF. That's its purpose, even if Commander47 doesn't think so.
P.S. The vacuum reservoir maintains the vacuum level...whether engine is ON or OFF. That's its purpose, even if Commander47 doesn't think so.
Burning Brakes
Joined: Oct 2011
Posts: 956
Likes: 86
From: McDonough Georgia
And that is correct. One time with the engine off. Nothing else. Not a thing. It isn't even in the loop for anything.
The can has nothing to do with the cruise, the operation of the HVAC switches. Nothing.
It is what it is. It is a can that stores vacuum to operate the lights. One time, and one time only with the engine off.
That's it. Nothing else. It is as clear as that.
Check this link.
http://www.corvette-restoration.com/...ers/vacuum.pdf
Burning Brakes
Joined: Oct 2011
Posts: 956
Likes: 86
From: McDonough Georgia
BTW, do your hvac switches work with the engine off? Do the power brakes work with the engine off? Does cruise control work with the engine off? Does your vacuum advance work with the engine off?
Answer: No. Because there is no vacuum source with the engine off.
After you shut off the engine, can you turn off the lights and have them go down?
Answer: Yes, vacuum in the can operates them.
Answer: No. Because there is no vacuum source with the engine off.
After you shut off the engine, can you turn off the lights and have them go down?
Answer: Yes, vacuum in the can operates them.
Pro
Joined: Aug 2013
Posts: 591
Likes: 3
From: Monroe Washington
My PO had more dollars than sense and threw money at the car without ever diagnosing the issues himself... At least it seems that way... Simply because I pushed a 'plunger' in under the dash to get the lights to function properly... And he said he couldn't get them to go down in almost 2 years...
It's little things like that, that I've been finding with all my cars 'issues'... And I couldn't be happier for it! I think his decision to buy a 2012 vette was a better decision for him... To each their own...
It's little things like that, that I've been finding with all my cars 'issues'... And I couldn't be happier for it! I think his decision to buy a 2012 vette was a better decision for him... To each their own...
