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Topic: Headlights and vacuum issues

in Forum: C3 General Discussion

Headlights and vacuum issues

Posted: 4/27/25 10:41am Message 1 of 14
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Vette(s): 1978 Corvette Light Blue Pulled from the swamps of Miami! Its a driver and back on the road!

So I am having issues with the headlights not opening up after pulling the switch. If I get out and tug on the passenger side lamp it pops right up and a few seconds the driver side will raise up. I mentioned this to my mechanic and he says its not a vacuum issue otherwise they would not raise after I tug on it. I was giong to start with the vacuum lines but if this is true then where do I start.  I will turn on the light switch and drive around for 20 minutes and nothing ever happens. Once in a blue moon  the drivers side will come up but  very rare and it will not bring up the passenger side.

 

Any ideas where to start?

 

Babyblue78




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Re: Headlights and vacuum issues

Posted: 4/27/25 2:01pm Message 2 of 14
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Grapevine, TX - USA
Joined: 8/26/2006
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Vette(s): 1972 LT-1 convertible with factory air. 2017 Black Rose Grand Sport convertible.

What about the pull down switch under the dash?




   

Re: Headlights and vacuum issues

Posted: 4/27/25 9:34pm Message 3 of 14
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Cana, VA - USA
Joined: 7/3/2016
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Vette(s): 1975 Stingray 71 350 engine Flat top pistons Sniper fuel injection Hyperspark ignition Vintage Air air conditioning Borgeson power steering box

Could it be low vacuum?  Maybe starting the headlight up gets it past the hard part of the cycle.  Just a thought. . .




   

Re: Headlights and vacuum issues

Posted: 4/27/25 11:03pm Message 4 of 14
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Grapevine, TX - USA
Joined: 8/26/2006
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Vette(s): 1972 LT-1 convertible with factory air. 2017 Black Rose Grand Sport convertible.

Maybe a vacuum relay.




   

Re: Headlights and vacuum issues

Posted: 4/28/25 9:42am Message 5 of 14
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Waterford, MI - USA
Joined: 9/13/2002
Posts: 1749
Vette(s): 1973 Red coupe

I had a similar issue

Driverside Popped right up but the passenger side was very lazy 

ended up being the actuator seal was split. Could not see the issue until after I removed it from the car and pulled the bellows off the shaft.

 




Brian - NCM Lifetime Member

73 coupe L48, Flat-top pistons, Performer RPM Heads, Crane Cam and roller rockers, Holley 650 vac sec. Performer intake,
3.55 gear BTO 200-4R trans,
Leather seats, Seatbelt Plus 3point seatbelts, Pioneer CD player
Magnaflow Exhuast System

Dewitt radiator and dual electric fans
Borgeson Steering box
 


Re: Headlights and vacuum issues

Posted: 4/28/25 5:48pm Message 6 of 14
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Vette(s): 1978 Corvette Light Blue Pulled from the swamps of Miami! Its a driver and back on the road!

Pull down switch is working fine. If open and pull down they stay out. Pushing in the knob they go down immediately.




Re: Headlights and vacuum issues

Posted: 4/28/25 5:49pm Message 7 of 14
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Vette(s): 1978 Corvette Light Blue Pulled from the swamps of Miami! Its a driver and back on the road!

Ok I had replaced the seals and should be good but will try but then how is it able to pop up if seals are torn?

 

Thanks for the info will check it out.




Re: Headlights and vacuum issues

Posted: 4/28/25 5:51pm Message 8 of 14
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Vette(s): 1978 Corvette Light Blue Pulled from the swamps of Miami! Its a driver and back on the road!

Yes I will start with the vacuum and I think last year when I fooled with it it was good. But will review all sugestions, that is why I did not think the mechanic was correct saying if it pops up on your tug its got enough vacuum, I know there is a pretty good spring inside and not sure if this is some issue also.

 

Thanks




Re: Headlights and vacuum issues

Posted: 4/29/25 9:16am Message 9 of 14
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Not sure if is called an actuator switch but there is a diaphragm under the nose right in front of the hood that controls the headlight vacuum as well.  I had the same problem on 1980 and after considerable inspection I switched the hoses on that diaphragm to see if the drivers side would be lazy instead. And sure enough it was. I replaced all the hoses and put a new diaphragm on it and it worked  much better though still a little slower on the right. Even the clamps were in bad shape as original.  I finally went to electric actuators with a conversion kit but mine is totally restomoded so only the windshield wipers runs on vaccum untill I can find a fix for that to. Also check your grommets in the sides of your light buckets they also deteriorate and can fall out causing the buck to bind ou while trying to open. Good luck.




Re: Headlights and vacuum issues

Posted: 4/30/25 2:05pm Message 10 of 14
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Grapevine, TX - USA
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Vette(s): 1972 LT-1 convertible with factory air. 2017 Black Rose Grand Sport convertible.
Babyblue 78 said:

Pull down switch is working fine. If open and pull down they stay out. Pushing in the knob they go down immediately.


Will the pull down switch "open" the headlights? 




   

in Forum: C3 General Discussion


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