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headlight vacuum help

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Old Sep 16, 2004 | 03:23 PM
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Default headlight vacuum help

I am having a real fit with my headlights. They were working fine and I did some dash work and now they won't work at all. I have checked the headlight switch with a vacuum pump and the pull-down switch and both are functioning properly. I checked the vacuum tank and it holds vacuum fine. I have 15 lbs. of vacuum at the manifold. When I check the tank at the relay valve hose connection the drivers side has 15 lbs of vacuum and the passenger side is zero. Anyone have a clue what I have to do to get my lights to work again? Thanks, Wells
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Old Sep 16, 2004 | 03:36 PM
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Sounds like a broken tee to mee.
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Old Sep 16, 2004 | 04:25 PM
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When you did your dash work, did you remove the hose from the switch or the manual pulldown switch. The hose can NOT be switched around on the nipples. I had a similar problem for a good year. It wound up being the hoses on the pull down switch hoses were not pushed on fully.

Also check to see where the hoses go through the firewall. After many years they tend to be brittle and are less forgiving with pulling on them.

Good Luck.
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Old Sep 16, 2004 | 04:36 PM
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Default Vacuum

Originally Posted by wellsw
I am having a real fit with my headlights. They were working fine and I did some dash work and now they won't work at all. I have checked the headlight switch with a vacuum pump and the pull-down switch and both are functioning properly. I checked the vacuum tank and it holds vacuum fine. I have 15 lbs. of vacuum at the manifold. When I check the tank at the relay valve hose connection the drivers side has 15 lbs of vacuum and the passenger side is zero. Anyone have a clue what I have to do to get my lights to work again? Thanks, Wells


Did you disconnect/reconnect the heater/AC hoses?
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Old Sep 16, 2004 | 10:48 PM
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What tee are you talking about? On the vacuum tank?
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Old Sep 16, 2004 | 10:48 PM
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Did not touch Heater/AC lines
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Old Sep 16, 2004 | 11:02 PM
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I have tried all combos for the blue and white hoses off the light switch the pull down is already color coded on both the plug in and the switch. Also I tried disconnecting the small line from the three line check valve and plugging the valve which take the two switches out of the loop and still the lights won't pop up.
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Old Sep 16, 2004 | 11:25 PM
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You may need the trusty old troubleshooting guide if you don't already have it.
http://www.corvette-101.com/ "vacuum trouble"

Try completely bypassing the check valve....just to see what happens.
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Old Sep 17, 2004 | 06:09 AM
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You can crimp the hose as well when you put the dash back together and bolt the steering wheel bakc in place. That's what I did with mine. Lowered the dash and it started working.
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Old Sep 17, 2004 | 11:29 AM
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Originally Posted by wellsw
What tee are you talking about? On the vacuum tank?
If I understood correctly, you checked the vacuum at the lines in the very front where they connect to the relays, yes? Oh wait, nevermind. After thinking through it more carefully, that wouldn't matter. If the tee was broken, you'd be losing vacuum at both relays. Nevermind. I'll give it some more thought. Got a meeting to run to right now...
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