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Topic: Headlights and vacuum issues

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Headlights and vacuum issues (1/10)
 4/27/25 10:41am
Babyblue 78
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1978 Corvette Light Blue Pulled from the swamps of Miami! Its a driver and back on the road!


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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 (2/10)
 4/27/25 2:01pm
F4Gary
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Grapevine, TX - USA

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What about the pull down switch under the dash?



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Re: Headlights and vacuum issues (3/10)
 4/27/25 9:34pm
BillHanna
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Cana, VA - USA

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



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Re: Headlights and vacuum issues (4/10)
 4/27/25 11:03pm
F4Gary
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Grapevine, TX - USA

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Maybe a vacuum relay.



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Re: Headlights and vacuum issues (5/10)
 4/28/25 9:42am
RedwingvetteLifetime Member
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Waterford, MI - USA

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Joined: 9/13/2002
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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.

 



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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
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Re: Headlights and vacuum issues (6/10)
 4/28/25 5:48pm
Babyblue 78
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Pull down switch is working fine. If open and pull down they stay out. Pushing in the knob they go down immediately.



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Re: Headlights and vacuum issues (7/10)
 4/28/25 5:49pm
Babyblue 78
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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.



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Re: Headlights and vacuum issues (8/10)
 4/28/25 5:51pm
Babyblue 78
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1978 Corvette Light Blue Pulled from the swamps of Miami! Its a driver and back on the road!


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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



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Re: Headlights and vacuum issues (9/10)
 Yesterday 9:16am
RedRadResto=FastC3*8
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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.

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Re: Headlights and vacuum issues (10/10)
 Today 2:05pm
F4Gary
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Grapevine, TX - USA

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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? 



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