Headlight Switch Question?
Thread Starter
Instructor
Joined: Dec 2003
Posts: 177
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From: Sylacauga Alabama
Headlight Switch Question?
I just installed a new headlight switch on my 79 L-48. I am so happy I have gauge lights now, however when I pull the swich to turn my light on they won't come up. I put my vacuum hoses back the same way they came off. Here's where it get interesting, I can pull my valve at the bottom of the steering colum and they will go up. When I push my headlight switch rod in to close they won't, but I can push the valve and they will go down? 
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)
Vacuum problem.
Did you put the hoses on the correct port? Here's a diagram for 73 to 79 Vettes http://s243.photobucket.com/albums/ff91/petes74ttop/ PG.
Race Director
Joined: May 2006
Posts: 16,528
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From: Dayton, Ohio
Back to your other problem--try this just for fun--try pulling the headlight switch out very very slowly and see if the lights will come up if they do you have the hoses switched.
Race Director
Joined: May 2006
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From: Dayton, Ohio
Le Mans Master
Joined: Aug 2006
Posts: 7,417
Likes: 1,554
From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
Electrical side of switch good-Vacuum side not working
My guess is that you have the vacuum hoses hooked up correctly but that your new switch is not working properly.
When you pull the headlight switch out the vacuum is blocked, that makes the head lights go up.
If you leave the headlight switch pushed in (the off position), the vacuum goes thru the headlight switch and the vacuum then goes thru the pull down switch. If you pull down the override switch the vacuum is blocked at that point, and that makes the headlights open. PG.
When you pull the headlight switch out the vacuum is blocked, that makes the head lights go up.
If you leave the headlight switch pushed in (the off position), the vacuum goes thru the headlight switch and the vacuum then goes thru the pull down switch. If you pull down the override switch the vacuum is blocked at that point, and that makes the headlights open. PG.
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Thread Starter
Instructor
Joined: Dec 2003
Posts: 177
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From: Sylacauga Alabama
Yeah all of my vacuum worked perfect before I switched it out. The only reason why I changed it was I had no gauge lights. NOW, I have gauge lights with a funky vacuum problem..... Things that make you go hummmmmm.........
I will troubleshoot tonight and get back with y'all....
I will troubleshoot tonight and get back with y'all....
Race Director
Joined: Oct 2000
Posts: 12,640
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From: Shamong, NJ
It is very possible that you got a bad switch. About 2 years ago there was a batch of bad switches on the market. The electrical part worked fine, but the vacuum didn't. I remember seeing more trouble with 68-77 switches, but the 78-82's were effected also. Often you could actually hear the vacuum leaking with the bad switches.
I haven't seen any bad switches in a while, but it doesn't mean that it doesn't happen. If you got it from a Vette vendor, you may have even gotten old, bad, inventory, from a couple years ago.
I haven't seen any bad switches in a while, but it doesn't mean that it doesn't happen. If you got it from a Vette vendor, you may have even gotten old, bad, inventory, from a couple years ago.
Race Director
Joined: May 2006
Posts: 16,528
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From: Dayton, Ohio
It is very possible that you got a bad switch. About 2 years ago there was a batch of bad switches on the market. The electrical part worked fine, but the vacuum didn't. I remember seeing more trouble with 68-77 switches, but the 78-82's were effected also. Often you could actually hear the vacuum leaking with the bad switches.
I haven't seen any bad switches in a while, but it doesn't mean that it doesn't happen. If you got it from a Vette vendor, you may have even gotten old, bad, inventory, from a couple years ago.
I haven't seen any bad switches in a while, but it doesn't mean that it doesn't happen. If you got it from a Vette vendor, you may have even gotten old, bad, inventory, from a couple years ago.
Team Owner
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St. Jude Donor '11
Last edited by Yello95; Jul 28, 2008 at 12:18 PM.
Race Director
Joined: May 2006
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From: Dayton, Ohio
Switching the hoses wont work but bending the tabs back and flipping the valve will work.
Thread Starter
Instructor
Joined: Dec 2003
Posts: 177
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From: Sylacauga Alabama
Y'all,
I pulled my switch out and heard nothing but and air leak at the switch, so I decided to switch the hoses. They work perfect(pull out they go up with gauge lights, push in and they go down perfect)Yahoo.... The crazy thing is that I have a build manual and I plumbed it the way it said???? Oh well new switch is in a working perfect. Thanks for all of the help.
I pulled my switch out and heard nothing but and air leak at the switch, so I decided to switch the hoses. They work perfect(pull out they go up with gauge lights, push in and they go down perfect)Yahoo.... The crazy thing is that I have a build manual and I plumbed it the way it said???? Oh well new switch is in a working perfect. Thanks for all of the help.
Drifting
Joined: Apr 2008
Posts: 1,305
Likes: 2
From: Lewisburg WV
thegazman
The feds require the lights to open when vacuum is lost. Earlier vehicles opened with vacuum and was a hazard when driving at night as the lights would close when vacuum was lost. This could be dangerous on a curvy road during darkness. Often when you see a Vette sitting with one light up or both it's because of a problem with the lighting vacuum system and the light(s) won't stay down.
Race Director
Joined: May 2006
Posts: 16,528
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From: Dayton, Ohio
The feds require the lights to open when vacuum is lost. Earlier vehicles opened with vacuum and was a hazard when driving at night as the lights would close when vacuum was lost. This could be dangerous on a curvy road during darkness. Often when you see a Vette sitting with one light up or both it's because of a problem with the lighting vacuum system and the light(s) won't stay down.
Drifting
Joined: Apr 2008
Posts: 1,305
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From: Lewisburg WV
thegazman
Ken
Race Director
Joined: May 2006
Posts: 16,528
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From: Dayton, Ohio
Roger.. you are so correct and I am absolutely wrong. Thank God we have people with your knowledge on this forum to keep us straight. I made some assumptions that were incorrect. I appreciate your patience with me. You should have called me a dumb a--. Plus if I would have had enough sense to look at your profile and see your occupation maybe I would have checked my facts before making another statement. Thank you for your knowledge and all the valuable information you provide the forum members.
Ken
Ken
This really is a great forum and I'm happy to be a part of it.
