79 Headlight switch vacuum question
Thread Starter
Burning Brakes
Joined: Nov 2004
Posts: 1,084
Likes: 52
From: Grand Rapids Michigan
79 Headlight switch vacuum question
I'm putting a 79 dash back together. Before I install the speedo/tach unit I want to be sure I don't have any vacuum issues with the headlight switch in the dash. My headlights turn on but they don't come up. With the car running...when I turn the headlights on I get a continuous vacuum hiss from the switch and no movement from the headlight doors. If this is ok I will button up the dash and move to under the hood to look for trouble. The override switch does not do anything in either position.
Thanks
Mike
Thanks
Mike
Le Mans Master
Joined: Oct 2006
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From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
Running and you pull the switch the lights should come up.
I think Willcox has a vacuum diagram on his site. I wouldn't put the dash back together until I knew all works OK. But that's me. I don't think taking the dash apart is all that much fun.
I think Willcox has a vacuum diagram on his site. I wouldn't put the dash back together until I knew all works OK. But that's me. I don't think taking the dash apart is all that much fun.
Race Director
Joined: May 2006
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From: Dayton, Ohio
I was going to say because of the hiss that you have the 2 hoses switched at the HL switch but then you said the bypass doesn't work. As Tim said check out the Willcox diagram and make sure you have all the hoses right.
Thread Starter
Burning Brakes
Joined: Nov 2004
Posts: 1,084
Likes: 52
From: Grand Rapids Michigan
Thanks Guys,
I agree with checking the diagrams before buttoning it up. Am I going nuts
or do the AIM and the Willcox diagrams contradict each other? The Willcox dia says "source vacuum to rear" and shows visually the source line to the port on the switch closest to the rear of the car when installed. The AIM on sheet 7 in 12C shows the opposite. I set mine up per the AIM diagram and going to copy Willcox for input.
I agree with checking the diagrams before buttoning it up. Am I going nuts
or do the AIM and the Willcox diagrams contradict each other? The Willcox dia says "source vacuum to rear" and shows visually the source line to the port on the switch closest to the rear of the car when installed. The AIM on sheet 7 in 12C shows the opposite. I set mine up per the AIM diagram and going to copy Willcox for input.
Le Mans Master
Joined: Aug 2006
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From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
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Vacuum Connections!
Willcox is correct, the AIM in not.
Here's another diagram.
Here's another diagram.
Last edited by Peterbuilt; Mar 16, 2010 at 10:35 PM.
