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1975 Headlight question

Old Apr 17, 2023 | 04:57 PM
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Default 1975 Headlight question

My lights do come up but takes about 8 seconds. I know there are the vacuum lines, actuators and relays. Got an opinion on which one might be the issue?
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Old Apr 17, 2023 | 05:03 PM
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Not certain without testing. Fairly easy to test for leaks. Hole in bottom of the relay valve plugged up is a possibility. Bad seal, seals in actuators. The list goes on.
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Old Apr 17, 2023 | 05:46 PM
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probably actuator seals
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Old Apr 17, 2023 | 07:01 PM
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http://www.corvette-101.com/vacuum.htm

Check each part starting at the filter.

I agree, many times it's the seals.


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Old Apr 17, 2023 | 07:22 PM
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While its just a guess, I've fixed mine and other people's headlights by putting the seal kit shown above on the actuators. Less than $20 per side to me is cheap enough to try. I just did mine again (the first time over 10 years ago) and my passenger side now snaps up instantly and my drivers side went from not going up, so being a split second behind the passenger side. So, they both now work every time.
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Old Apr 20, 2023 | 05:37 AM
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Thanks for all the help. Will start going through it soon. For the first time I drove it for a while at night. When I turned off the lights the right one closed pretty quick but the left one took about 30 seconds. Does this narrow down which area to concentrate on first? Thanks!
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Old Apr 20, 2023 | 06:28 AM
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Sort of. The left side relay. The left side actuator.
but in all honesty, brand new it took a couple seconds to raise. And most often one, then the other. This is normal.
30 seconds to go down does sound like a vacuum leak or a plugged vent hole in the bottom of the relay valve.
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Old Apr 20, 2023 | 07:17 AM
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I agree with above to check the relays exhaust port...
When new there was a piece of black foam covering that rectangle area.
Over time the foam disintegrates.
An open cavity is an invitation for small critters...
If you can't exhaust, you can't change state.
Here is a photo where I colored in White the approximate shape and location of the exhaust port, some call it the smiley face....





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