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Vacuum Headlight Relay Question 79vette

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Old Jan 14, 2013 | 09:55 PM
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Default Vacuum Headlight Relay Question 79vette

Ok, so my project 79 vette has major vacuum issues. Tonight I was checking the headlight vacuum system per a schematic. The schematic shows two relays (one for each light), but when I started checking inside it appeared like there was only one relay, but there was this adapter that had the same connection ports as a relay.
Is there any such thing as only one relay on a 79 vette? The hoses for one of the headlights were just dangling/not connected.
Here is a pic of the adapter which was located right next to (and possibly connected to) the one relay that was present:
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Old Jan 14, 2013 | 10:39 PM
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That's a relay.
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Old Jan 14, 2013 | 10:41 PM
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Originally Posted by '75
That's a relay.


That is the bottom on one of your relays, it needs three hoses connected, all color coded to the dots painted on the relay, you can just see them in your photo. Oh and there should be a foam filter in that little square doohickey on the end.

Cheers, Dennis.
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Old Jan 15, 2013 | 03:52 AM
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http://willcoxcorvette.com/product_i...ducts_id=27391

Here are some good pictures here. Willcox has them all.
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Old Jan 15, 2013 | 06:38 AM
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Here is a handy guide I use when troubleshooting my headlight components. Shows you what everything is and how to test it to make sure it works correctly.

http://www.corvette-101.com/vacuum.htm
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Old Jan 15, 2013 | 10:17 AM
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Order the 79 assembly instruction manual (AIM); it will help you getting your car back together. While you're at it, order a 79 owner's manual if you do not have one.

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Old Jan 15, 2013 | 01:27 PM
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Thanks again for the help.
Had I used a mirror to be able to see underneath better I would have seen it was a relay like several of you suggested. Not sure why it was mounted directly next to the other relay...maybe that's normal, but all the diagrams give the impression the two relays would be separated, one on each side of centerline.
Also, I am giving up on my Chiltons manual and have ordered an AIM from Wilcox.
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Old Jan 15, 2013 | 03:24 PM
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Originally Posted by FHPauly
...I am giving up on my Chiltons manual...
Good for you. Chilton and Haynes are handy every now and then, but are usually very generic.

...and have ordered an AIM from Wilcox...
Also good for you. AIMs are model year specific.

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Old Jan 15, 2013 | 03:56 PM
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Originally Posted by FHPauly
Thanks again for the help.
Had I used a mirror to be able to see underneath better I would have seen it was a relay like several of you suggested. Not sure why it was mounted directly next to the other relay...maybe that's normal, but all the diagrams give the impression the two relays would be separated, one on each side of centerline.
Also, I am giving up on my Chiltons manual and have ordered an AIM from Wilcox.
Get an FSM or Factory Service Manual, while you're at it. The only thing is to make sure they put one out in 79', because some of the post 74's (1975, 76, etc) use the 74' FSM and added an update manual for the minor differences.

The FSM is highly educational too! Each chapter covers theory and operation very, very well, before going into the R&R and Troubleshooting.
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