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headlight question again!

Old Apr 11, 2017 | 08:05 PM
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Default headlight question again!

What would cause a both headlights to slowly creep open partially and then slowly creep closed when you shut off the car?

Also, while digging around under the dash, I noticed that the white hose going from the over ride switch to the head light relay has been spliced twice under the dash. Did it come that way from the factory? Looks like something a previous owner messed up.

Last edited by loflite; Apr 11, 2017 at 08:54 PM.
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Old Apr 11, 2017 | 09:07 PM
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Viewing your profile, I see a '69 and a '76. Don't know which car you are referring to. A '69 only uses a single relay for the headlights which would give very similar symptoms in both headlight doors. If you still have the original headlight relay I would suspect that.

There should not be any cuts or splices to other components in the control vacuum hose going to the front relay.
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Old Apr 11, 2017 | 09:14 PM
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Originally Posted by Dave J
Viewing your profile, I see a '69 and a '76. Don't know which car you are referring to. A '69 only uses a single relay for the headlights which would give very similar symptoms in both headlight doors. If you still have the original headlight relay I would suspect that.

There should not be any cuts or splices to other components in the control vacuum hose going to the front relay.
Thanks, yes, I'm working on the '69. The control vacuum hose is spliced together twice like it was cut and then patched under the dash only.

Thanks again.
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Old Apr 12, 2017 | 11:00 AM
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No wiper door problems?

I'd check the manifold supply line check valve too.
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Old Apr 12, 2017 | 12:58 PM
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Originally Posted by theandies
No wiper door problems?

I'd check the manifold supply line check valve too.
No wiper door problems. I already replaced the check valve and filter. Tested the check valve before I put it in. Planning replacing the control vacuum line before I put it all together and see if it still does the headlight thing.
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Old Apr 12, 2017 | 04:26 PM
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If this is only on the headlamps then I'd suspect the vacuum relay is your issue. By default the system is designed to open if there is a failure. My guess is your system is losing vacuum and when you start it the relay position is in the "open" mode.

So if the relay has lost vacuum when you start the car, the doors will open and then as the car picks up vacuum, the top nipple will start pulling the plunger upward "lower" mode and pull the lamp downward.

Willcox


Last edited by Willcox Corvette; Apr 12, 2017 at 04:27 PM.
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Old Apr 13, 2017 | 06:43 PM
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Thanks Willcox. I've used your a lot of products and your very helpful videos too. The headlight creep happens only when I shut the car off. I'll play some more with it tonight after work.
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