79 vette Headlights

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Aug 28, 2009 | 11:54 AM

bronco68

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6th Gear

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79 vette Headlights

I am experiencing an issue with my headlights. all of a sudden they wouldn't come up when the switch was turned on. i can open them manually and they will stay on while running. if i pull the vacumn switch under the dash, they will stay up after engine is turned off. i pulled 25 inches of vacumn to the system and it will hold vacumn with engine off. where should i start. no vacumn leaks and everything works fine except coming up. the engine has 18 inches of vacumn at idle.
thanks
frustrated vette owner

Aug 28, 2009 | 12:51 PM

justaguy10825

Instructor

Joined: Sep 2006

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From: Searcy Arkansas

Bad light switch???

Aug 28, 2009 | 01:11 PM

bronco68

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6th Gear

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Does the light switch have a trigger to control the headlights? Is there a relay that controls the up down?

Aug 28, 2009 | 02:05 PM

Easy Mike

Team Owner

Joined: Jun 2000

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From: Southbound

Cruise-In II Veteran

Quote:

Originally Posted by bronco68

Does the light switch have a trigger to control the headlights? Is there a relay that controls the up down?

Yes. There is a vacuum line to the headlight switch. Pull the switch to turn on the lights and you send a vacuum signal to open the headlight doors.

The override under the dash bypasses the headlight switch and allows you to cycle the headlight doors a time or two with the engine off.

(I apologize for the original diagram. There are two of these available, an incorrect version and a correct one. I thought I had deleted the bad one, but --naturally-- deleted the good one.)

Last edited by Easy Mike; Aug 28, 2009 at 07:41 PM.

Aug 28, 2009 | 02:41 PM

bronco68

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Thank you very much.

Aug 28, 2009 | 02:59 PM

...Roger...

Race Director

Joined: May 2006

Posts: 16,528

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From: Dayton, Ohio

Quote:

Originally Posted by bronco68

Thank you very much.

Bronco the above vacuum diagram is wrong don't use it your headlights won't work correctly.

Aug 28, 2009 | 04:35 PM

bronco68

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Thanks

Thank you for the heads up. i will trace thelines before i do any replacements.

Aug 28, 2009 | 04:38 PM

Peterbuilt

Le Mans Master

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From: mount holly NC

2025 c3 ('74-'82) of the Year Finalist - Unmodified

2019 C3 of Year Finalist (appearance mods)

Here's a corrected diagram. PG.

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Aug 28, 2009 | 05:14 PM

bronco68

Thread Starter

6th Gear

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Thank you,
i see where the location of the lines are different at the headlight switch.

Aug 28, 2009 | 06:51 PM

#10

Peterbuilt

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From: mount holly NC

2025 c3 ('74-'82) of the Year Finalist - Unmodified

2019 C3 of Year Finalist (appearance mods)

The troubleshooting guide at www.corvette-101.com/ is helpfull. PG.

Aug 28, 2009 | 06:58 PM

#11

21boy

Racer

Joined: Sep 2008

Posts: 402

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From: Space Coast Florida

You're lights turn on though when you pull your switch, just not up? Sounds like either the switch isn't holding well or perhaps the relays may have an issue???

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