Please help! Why headlight opens up when car is turned off
Thread Starter
5th Gear
Joined: Mar 2005
Posts: 5
Likes: 0
Please help! Why headlight opens up when car is turned off
undefinedWhat would cause 1 of the headlights to open up and stay open when my 1970 corvette is turned off? Both operate fine when car is running.
Melting Slicks
Joined: Feb 2004
Posts: 2,435
Likes: 0
From: largo florida
There is a check valve that is supposed to stop vacuum from creeping back and sucking the headlights up once the engine is shut off. The check valve is most likely bad.
http://www.zip-products.com/Zip/prod...A29A415D04C757
http://www.zip-products.com/Zip/prod...A29A415D04C757
Last edited by lostpatrolman; Mar 16, 2005 at 12:16 AM.
Melting Slicks
Joined: Jan 2005
Posts: 3,028
Likes: 0
From: Madison Ms
Originally Posted by lostpatrolman
There is a check valve that is supposed to stop vacuum from creeping back and sucking the headlights up once the engine is shut off. The check valve is most likely bad.
http://www.zip-products.com/Zip/asse...ges/M-3105.JPG
http://www.zip-products.com/Zip/asse...ges/M-3105.JPG
Hey.........I need one of those!!
Racer
Joined: Dec 2004
Posts: 319
Likes: 4
From: Suisun City, CA
I recommend the Vette vacuum troubleshooting guide. I ordered it from Mid-America. The guide has two sections: (A) Tutorial (B) Troubleshooting. After some studying, you too can be an expert in the light and wiper vacuum system.
Le Mans Master
Joined: Oct 2001
Posts: 5,943
Likes: 3
From: Wildwood IL
Originally Posted by reckerrp98
is that check valve up by the firewall or down by the vacuum tank? i have the same problem too!
Eddie
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Melting Slicks
Joined: Nov 2001
Posts: 2,668
Likes: 43
From: Eastern US XX
Originally Posted by reckerrp98
is that check valve up by the firewall or down by the vacuum tank? i have the same problem too!
Burning Brakes
Joined: Nov 2003
Posts: 990
Likes: 0
From: North Texas
Originally Posted by lennyv
undefinedWhat would cause 1 of the headlights to open up and stay open when my 1970 corvette is turned off? Both operate fine when car is running.
Le Mans Master
Joined: Jun 2002
Posts: 8,339
Likes: 24
From: I can walk to MA
Originally Posted by lostpatrolman
There is a check valve that is supposed to stop
vacuum from creeping back and sucking the headlights up once the
engine is shut off. The check valve is most likely bad.
http://www.zip-products.com/Zip/prod...A29A415D04C757
vacuum from creeping back and sucking the headlights up once the
engine is shut off. The check valve is most likely bad.
http://www.zip-products.com/Zip/prod...A29A415D04C757
stored in the tank from sucking air during periods of low vacuum in
the manifold. The headlight actuators require vacuum to pull up and
vacuum to pull down. A leaky check valve would prevent them from
moving after the car is off. Am I missing something here ?
This is Lenny's second thread on this. I posted my guesses in the first.
I'll copy it here:
So, the lights are down - then when you turn the engine off,
the passenger side pops up ?
I'd say one of two issues:
1 - Someone named Bubba worked on the vacuum headlight
system and mucked it up.
2 - The vacuum relay has a leak to the UP side of the vacuum actuator.
Hmmm - maybe 3 :
There is a vacuum over-ride switch under the steering column.
This is used to hold the headlights in the up position when turning off
the engine. It's a little black **** that you push
up and down. Mine was snapped right off. Check it out.
Oh yeah - welcome to the madness !!!
Race Director
Joined: Feb 2005
Posts: 16,100
Likes: 17
Originally Posted by lennyv
undefinedWhat would cause 1 of the headlights to open up and stay open when my 1970 corvette is turned off? Both operate fine when car is running.
Race Director
Joined: Feb 2005
Posts: 16,100
Likes: 17
Originally Posted by lennyv
undefinedWhat would cause 1 of the headlights to open up and stay open when my 1970 corvette is turned off? Both operate fine when car is running.
Team Owner
Joined: Jun 2004
Posts: 20,216
Likes: 4
From: Smile, it's just the internet.
This stuff is so easy to check, it's best to test the components before replacement. This technology is fifty years old... Take the check valve out (no tools needed) and suck/blow on it. If you get flow in both directions, it's bad.
$50 on eBay for an electric vacuum pump is the first investment you should make if you have ANY vaccum problems on an old Vette. You'll wonder how you worked on the system without one.
$50 on eBay for an electric vacuum pump is the first investment you should make if you have ANY vaccum problems on an old Vette. You'll wonder how you worked on the system without one.
Pro
Joined: Aug 2003
Posts: 677
Likes: 5
From: Cary North Carolina
When the control valve gets vacuum then the lights will be down. If the control valve gets no vacuum then the lights will go up. In otherwords a failure in the control line or switch will cause the lights to fault in the up position. When you turn your car off the control valve is loosing vacuum before the actuator and the lights go up. Might be a leak in the control line somewhere.
Safety Car
Joined: Jan 2004
Posts: 4,776
Likes: 142
From: North of Atlanta GA
St. Jude Donor '05
Originally Posted by lennyv
undefinedWhat would cause 1 of the headlights to open up and stay open when my 1970 corvette is turned off? Both operate fine when car is running.
