Topic: Headlight Help
in Forum: C3 Body
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I hope I posted this in the right section.
The headlight doors on my '79 will not come up on their own any more.
When I first bought the car 4 years ago they both came up, although the passenger side one was a bit lazy. At the time I would gently help it up with my hand and they remained up without being droopy at all.
However, during the spring of '07 they stopped reacting to the headlight switch being turned ON at all. (The lights lit up with absolutely no hint of trying to raise up.) I was able to use the headlights by pushing up on the headlight doors from under the front bumper and they remained UP until I turned the headlight switch OFF. Also, I noticed that with the headlights ON and the headlight doors UP, they would remain in the UP position when I shut OFF the motor while leaving the headlight switch ON.
"Ya follow me?
With the motor running I don't hear any sucking vacuum sounds up front with the headleghts ON or OFF with the headlight doors up or down.
I want to start off on the right foot with this.
Any advice is appreciated!
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I have not checked the override switch under the column.
How would I get access to it? What does it look like?
I'm not an experienced mechanic, but I'd like to tackle this by myself. I've got all winter to learn.
As far as bad relays or vacuum canisters go, would'nt I hear a tell tale sucking sound if I was losing vacuum through a break in the system?
Thanks for your input!
On the lower edge of the dash ,where your legs go ,you should see a little black knob sticking down,Mine is to the left of the steering column,with the engine running pull down on the knob,to raise the lights,push it up and it should lower the lights,its an override so you can open them up to change the bulbs without blinding yourself Ron 78 2007-11-26 18:48:20
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Vette(s): 1975 metallic blue coupe with t-tops,L48, t/t steering, black leather interior. 1990 L98, white/red leather interior, auto,a/c
you may not hear vacuum leaks at the cannisters or relays. the best guide on how to check them is at http://www.corvette-101.com. it is a free guide that you can print out and he explains on how to troubleshoot the whole system.
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Ill ditto eddie 20875's recommendation of corvette-101. By taking the process one step at a time you are likely to find the problem. Dont be surprised if its a combination of things that caused it, based on your description. Most of us have had headlight problems...or will have, at one time or another and I found that the corvette-101 site to be a fantastic help. Some of the parts are a bit difficult, but not impossible, to get to, so take your time and take your meds before you start 
. Let us know what you find.
. Let us know what you find.Ron,
I operated the override switch but got no difference. I left it back in the pushed up position which keeps the headlight doors down.
I can definitely rule that out as a problem at this point.
Thanks for your input!
Next stop is Corvette 101. Wish me luck!
Kevin
You've lost system vacuum somewhere. Since neither the light switch nor the override works, my guess is that your loss is on the intake manifold, or between the manifold and the light switch.
(large image modified to link)Adams' Apple 2007-11-28 06:18:28
And yes, you can often hear a vaccum leak. Finding the leak might be a two beer job, but you can hear them.
(large image modified to link)
OK. I've opened pandora's box here. However, I'm not at all discouraged. I'm real interested in figuring this out & I appreciate everyone's input.
I printed out the diagram for the headlight door vacuum from Corvette-101. I discovered the following;
The vacuum lines were taken off of the air tank and pieced together with a T-Bar connector. This allows the headlight doors to remain firmly up. I tried to re connect them to the air tank but the headlight doors would'nt come up on their own. I lifted them up with the light switch on and thay stayed up. However, they would not go down when I turned the light switch off.
I reconnected them with the (Bubbafied) T-Bar connectors and the headlight doors obediently went down when the light switch was turned off.
Additionally, there is a T-Bar vacuum hose connector installed just off of one of the two nipples that are on the same side of the Vacuum Acuator Relay up near the fire wall. I strongly suspect this T-Bar does not belong here.
This is a mess!
Note; In April of '07 I had some carb. work done. I strongly suspect that mechanic believed he was doing a good thing by bypassing the air tank with the vacuum lines. (He just never bothered to mention anything about it to me.) I think instead of fixing a problem with the vacuum headlight system, he just plain bypassed it. (He is deceased now. So, we'll never know exactly.)
I plan on buying a copy of "Trouble Shooting" It's a book offered in the Mid America Catalogue that deals with the Headlight and Wiper Systems in the C3's.
I'm hoping that it has detailed diagrams of where each and every vacuum line goes concerning this system.
At this point I'm leavin' it alone until I have some detailed diagrams.
Thanks to all of you who offered help. I'll be asking for more help on this once I have the right reference point to start from.
Kevin
in Forum: C3 Body
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