C3 Headlights
Le Mans Master
Joined: Jun 2004
Posts: 9,289
Likes: 16
From: Skippack PA
St Jude Donor '13
Originally Posted by ajstr1265
I have a 76 C3. When the car is running, the headlights operate properly. When I shut it off, either one or both pop up. Anyone have any ideas?
Use this great troubleshooting guide to help you figure out where the problem is:
http://209.183.231.72/corvette-101/vacuum.htm
Le Mans Master
Joined: Jun 2002
Posts: 8,339
Likes: 24
From: I can walk to MA
Originally Posted by TheKomoman
You have a vacuum leak somewhere in your system. Vacuum holds the headlights down, when you lose vacuum they come up. When your motor is running it's producing enough vacuum to hold the lights down, but when its shut off the system leaks and eventually the lights pop up.
Use this great troubleshooting guide to help you figure out where the problem is:
http://209.183.231.72/corvette-101/vacuum.htm
Use this great troubleshooting guide to help you figure out where the problem is:
http://209.183.231.72/corvette-101/vacuum.htm
actually stay down by themselves with no vacuum applied. They also
stay up with no vacuum applied. So, when the car is turned off,
some vacuum is "sneaking" into the "goes up port" of the actuator.
I agree with the last post ... a leak inside the relay would do it.
Thread Starter
Instructor
Joined: May 2005
Posts: 229
Likes: 0
From: Oreland PA
Thanks
THanks for all of the help. I actually looked in the Doc Rebild cat. Under the check valve part listing it said this will cause the headlights to pop up when the car is turned off. So I will try the least expensive first. Thanks again for everyone's help
Team Owner
Joined: Jun 2004
Posts: 20,216
Likes: 4
From: Smile, it's just the internet.
Test the check valve. Put the single nipple in your mouth and suck. Then blow. It should be impossible to one or the other (can't remember which). If you can suck AND blow, it's broken.
No jokes...
No jokes...
Burning Brakes
Joined: Feb 2005
Posts: 1,235
Likes: 0
From: Mesa AZ
Originally Posted by NHvette
True - sounds like a vacuum leak or faulty component, but the headlights
actually stay down by themselves with no vacuum applied. They also
stay up with no vacuum applied. So, when the car is turned off,
some vacuum is "sneaking" into the "goes up port" of the actuator.
actually stay down by themselves with no vacuum applied. They also
stay up with no vacuum applied. So, when the car is turned off,
some vacuum is "sneaking" into the "goes up port" of the actuator.
there is not constant vacuum on the lights. only to open and close.
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