Yet another headlight problem
Thread Starter
Pro
Joined: Feb 2005
Posts: 616
Likes: 2
From: Sedalia MO
Yet another headlight problem
First and foremost, yes I did a search. The problem is my headlights will not go up, or turn on. While looking around under the hood, I found a vacuum line with a black locking cap hanging down from the driver's side mid frame, below some sort of light relay. Also, I see the previously mentioned relay that does not have a wire hooked up where it says lights. Problem is, I do not see a wire. Any ideas? Thank you in advance. If you all don't immediately know what i am talking about, I will take pictures tomorrow.
Team Owner
Joined: Jun 2000
Posts: 38,923
Likes: 1,482
From: Southbound
Cruise-In II Veteran
Raising and lowering the headlight doors is 100% vacuum. Lights on or off is 100% electrical. You have two different problems. Will the headlights raise using the override under the steering column?
Post a pic of what you're calling a vacuum line with a black cap.
The gray and white wires you found are not likely to be headlights. Headlight switches plug up off the main dash wiring harness.
What model year do you have?
Post a pic of what you're calling a vacuum line with a black cap.
The gray and white wires you found are not likely to be headlights. Headlight switches plug up off the main dash wiring harness.
What model year do you have?
Last edited by Easy Mike; Jun 21, 2013 at 02:45 PM.
Thread Starter
Pro
Joined: Feb 2005
Posts: 616
Likes: 2
From: Sedalia MO
I have a 78 anniversary. That is what I figured. No the lights will not raise with the override either. I did a vacuum test at different places all along the system and I am only getting 7 lbs. The windshield wipers work like a champ though. The car is heavily cammed though. I heard that may lower the vacuum pressure? I have no idea what cam either. How do i raise the vacuum pressure.
Thread Starter
Pro
Joined: Feb 2005
Posts: 616
Likes: 2
From: Sedalia MO
May be a stupid question more or less just to confirm that is does effect the vacuum, but when I press the brake pedal down, I hear a hiss. I am sure it is the booster. Breaks feel fine though. Can this affect my vacuum? I have had this car for two days, and so far the only issues are the headlights, bot vacuum and electrical, please someone help!
Le Mans Master
Joined: Aug 2006
Posts: 7,426
Likes: 1,559
From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
How To:
For the headlights not turning on:
The red wire brings power to the switch, you can check there and you can check the ground on the radiator support.
78 schematic:
http://www.vetteprojects.com/bmv/mis...tte%201978.pdf
For the headlights not going up and down:
http://www.corvette-101.com/vacuum.htm#top
The leaky booster is next.
The red wire brings power to the switch, you can check there and you can check the ground on the radiator support.
78 schematic:
http://www.vetteprojects.com/bmv/mis...tte%201978.pdf
For the headlights not going up and down:
http://www.corvette-101.com/vacuum.htm#top
The leaky booster is next.
Thread Starter
Pro
Joined: Feb 2005
Posts: 616
Likes: 2
From: Sedalia MO
Pete thank you! I saw the Corvette 101 during my search. I suspect that the way one of the the PO routed the vacuum assembly may be the culprit. I will take and post a pic. He has the lights, brakes, and wipers all t jointed off the intake. This car is gorgeous inside and out. If I can get these things fixed it would be perfect. He even disabled the dome and under dash lights. Don't get why he did that. And the guy who I bought it from put a Holley 750 on a mild rebuild. Thing runs real rich, like head ache rich, and the leaking booster isn't helping since the idle is steady when you depress the pedal.
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Le Mans Master
Joined: Aug 2006
Posts: 7,426
Likes: 1,559
From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
For the vacuum start at the manifold and cap off everything except the headlight system and follow the diagram step by step.
Between the age of our cars and the Bubba's that came before you never know what you may find.
Between the age of our cars and the Bubba's that came before you never know what you may find.
