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1978 headlight issues

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Old Jun 8, 2015 | 06:01 PM
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Default 1978 headlight issues

Having problems with my headlights, I can get them to go down when vacuum is hooked to base of carb, but they will not go up when the switch is pulled on. Running dual quads so I don't have a vacuum port at the intake. Any thoughts? Thank you. Ralph
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Old Jun 8, 2015 | 07:17 PM
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The headlights need vacuum to go up or down. Make sure that all of the hoses a hooked up correctly.
How To:
http://www.corvette-101.com/vacuum.htm
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Old Jun 8, 2015 | 07:40 PM
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Originally Posted by Ralph419
Having problems with my headlights, I can get them to go down when vacuum is hooked to base of carb, but they will not go up when the switch is pulled on. Running dual quads so I don't have a vacuum port at the intake. Any thoughts? Thank you. Ralph

If you don't have the hoses plumbed correctly they'll never work right.
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Old Jun 8, 2015 | 07:57 PM
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Originally Posted by toobroketoretire
If you don't have the hoses plumbed correctly they'll never work right.
Since they go down and not up do you think it is a vacuum issue?
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Old Jun 9, 2015 | 04:35 AM
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Originally Posted by Ralph419
Since they go down and not up do you think it is a vacuum issue?
There are different types of vacuum and headlamps need manifold vacuum. Typically manifold vacuum pulls 15-18 inches of vacuum while carb ports pull less to manage air fuel ratios.
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