Why do my headlight keep flipping up?
Thread Starter
Heel & Toe
Joined: Oct 2009
Posts: 23
Likes: 0
Why do my headlight keep flipping up?
I have a 1978 and everytime i drive it and turn it off the headlights flip up. All i have to do then is restart it and they go back down and then stay down, very weird. any ideas?
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,116
From: Crossville TN
The check valve is the most likely problem. A bad valve is essentially a very big leak in the system whenever the car is turned off. To check it out, go for a drive; when you come back, leave the car running and use a set of Vice-grip pliers to clamp-off the main vacuum 'feed' line that runs from the fitting on the intake manifold to that check valve. Then, turn off the car. If the headlights stay down, the check valve is your problem. If you want to replace it, buy 2 or 3; they lose their sealing capability much more quickly than they should [poor design, lousy replacement part quality, ethanol in fuel, etc.].
Team Owner
Joined: Sep 2006
Posts: 31,202
Likes: 4,287
From: Westminster Maryland
Hi Carl,
I believe Mike miss-typed.
The FILTER is white plastic, one hose in and one hose out. The CHECK VALVE is gray metal, one hose in, and one large hose and one small hose out.
It seems to me the problem has to be something other than the check valve. If it were the check valve the headlights would pop up EVERY time the engine's shut off, not just the first time.
Do the lights pop up immediately? If they do isn't it a relay/signal problem? If they take a few moments to pop up then it sounds like a vacuum leak that bleeds off the vacuum that holds the lights closed.
Regards,
Alan
I believe Mike miss-typed.
The FILTER is white plastic, one hose in and one hose out. The CHECK VALVE is gray metal, one hose in, and one large hose and one small hose out.
It seems to me the problem has to be something other than the check valve. If it were the check valve the headlights would pop up EVERY time the engine's shut off, not just the first time.
Do the lights pop up immediately? If they do isn't it a relay/signal problem? If they take a few moments to pop up then it sounds like a vacuum leak that bleeds off the vacuum that holds the lights closed.
Regards,
Alan
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer