Under Dash Vacum Line Help
Thread Starter
Advanced
Joined: Jun 2007
Posts: 58
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From: Winston-Salem N.C.
Under Dash Vacum Line Help
does anyone have a diagram of the under dash vacum line routing? previous owner ( i think his name was Bubba) made a mess of under dash wiring and vacum lines. i think i have a handle on it but one of the lines that goes to the headlight door opening switch that mounts beneath the dash has a tee inline (plugged with a trimscrew!) . should their be a tee there? any pics or diagrams would be greatly appreciated, also pics of where that switch mounts to the dash underneath.
thanks,chris
thanks,chris
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
What year C3 do you have? For that matter, filling out your profile will help us a lot when trying to walk through a problem with you. 
Here is a generic diagram but know that the later C3s had less vacuum stuff under the dash.
Here is a generic diagram but know that the later C3s had less vacuum stuff under the dash.
Race Director
Joined: Apr 2003
Posts: 19,344
Likes: 654
From: Tampa, Florida
Unfortunately DB's diagram is incorrect. The blue hose connected to the port closest to the firewall on the headlight switch goes to port closest to the floor on the pull down switch....
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
Hmm...seems there are more than a few wrong diagrams floating around. I didn't create it...just posted it, but I compared it to a later model vac diagram and IT'S incorrect as well based on your correction.
Race Director
Joined: Apr 2003
Posts: 19,344
Likes: 654
From: Tampa, Florida
Thers a few of them out there. At least one vendor has an incorrect diagram in their catalog!!!
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Advanced
Joined: Jun 2008
Posts: 58
Likes: 1
From: Eastampton NJ
on1wheel01:a) You need a source of vacuum to the two headlight "relays" between the headlights. b) You need a vacuum supply to the headlight override valve under the steering column, and c) a line (should already exist) going from the override valve to the headlight relays. This minimum would allow you to control the headlight doors with the override valve. If you brought vacuum to the headlight switch (should exist already) and brought the headlight switched vacuum to the ovrride valve it would work normally.
Race Director
Joined: May 2006
Posts: 16,528
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From: Dayton, Ohio
If you want the headlight switch to be included in the vacuum let me know and i will post that pic.
Last edited by ...Roger...; Jun 22, 2008 at 08:14 AM.
Drifting
Joined: Mar 2008
Posts: 1,900
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From: Nixa Missouri
Racer
Joined: May 2008
Posts: 421
Likes: 0
From: Mooresville NC
Thanx guys for the help.
That one seems the easiest, I just need to get a pull down switch and some air line and a new filter as mine touched a header. The car has been basterfied with wiring and air lines. I think ill hit up ebay for the parts i need. Again thanx guys
Here is bare minimum.You will use the pulldown under the dash to raise and lower the headlight buckets-use your headlight switch to turn on the beams.(ignore the text saying head lamp switch at the top)
If you want the headlight switch to be included in the vacuum let me know and i will post that pic.
If you want the headlight switch to be included in the vacuum let me know and i will post that pic.
Le Mans Master
Joined: Aug 2006
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From: mount holly NC
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Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
Are you sure the pulldown isnt stuffed under the dash or still mounted in the stock location?Also if you would like I can tell you how to hook it up using only the headlight switch and leaving the pull down switch out.
Racer
Joined: May 2008
Posts: 421
Likes: 0
From: Mooresville NC
Well under the dash is a nightmare with wires, i have no idea where the switch is suppose to be. And I am all ears to hear any thing to save mne from buying parts