C3 Vette Registry - The Best Resource on the Net for C3 Vettes! C3 Vette
Forums -> C3 Electrical
Not Logged In! Login or Register!  Users Online: 19 / Help 
Features  Find C3 Parts on ebay in only 2 or 3 clicks!  | Add YOUR C3 to the Registry

Supporting Vendors
Bair's Corvettes
Volunteer Vette Products
VetteBookStore.com
Mid America Motorworks
CorvetteClothing.com

C3 of the Month
None Current
Enter Yours Today!
Online C3 Show
13
C3s are Registered

Vanity Plates
FUN 71
fun71
Featured Links

Buy Now
Corvette: America's Sports Car Yesterday, Today, Tomorrow (Hardcover)
Corvette: America's Sports Car Yesterday, Today, Tomorrow (Hardcover)


GM Corvette 1963-82 (Chilton's Total Car Care Repair Manuals) (Paperback)
GM Corvette 1963-82 (Chilton's Total Car Care Repair Manuals) (Paperback)


Corvette 50th Anniversary
Corvette 50th Anniversary


The Corvette Dynasty (Hardcover)
The Corvette Dynasty (Hardcover)



| Hide Signatures and Profile Pics

 New Topic New Topic Post Reply Reply New Poll New Poll Search     Search Page [1]  
12/27/11 9:37pm - Original Message: 'Vacuum controls: headlight doors close but don't reopen on 68E'
theycallmered
Former Member
- Send Private Message


, - Australia

Vette(s):
Second-month production Shark, this 1968E was built up by original owner into 1969 ZR1 (L88 body with LT1 engine) for Club Racing. Body styling is from Maglioli's 1968 L88 "Le Mans" racer

Joined: 10/27/2010
Posts: 54
Since the headlight vacuum controls are related to electrical, I guessed a query belongs here? Car is a 68E.

I do have the vacuum troubleshooting manual, and the 68 assy manual; and between the pair of them I'd have reckoned I have all the bits connected correctly.

But:  with the headlight doors open, starting the car closes the doors briskly, and the headlights turn on and off with the switch but the doors don't re-open.

Neither override switch has any effect on the doors (even when I re-traced all and it appeared I had the rubber plug-ins at the override switches reversed).

Anyone clever enough to know what the problem is?

Thanks so much.


____________________________________
1968E (2nd month production) convertible first registered California 1967 and a retired SCCA race car.  It is still race prepped and built up as a '69 ZR1 (announced '69 but not built until '70); i.e., the L88 car with LT1 motor.


 Reply Reply  Quote Reply w/Quote
 
Support C3VR!
Suport our advertisers
12/27/11 11:36pm - Reply: 'Re: Vacuum controls: headlight doors close but don't reopen on 68E'
Adams' Apple Lifetime Member
Lifetime Member
Moderator
- Send Private Message


Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

Joined: 11/8/2003
Posts: 19449
Arrrrgh! Not another vacuum problem!!!Censored
LOL
So the doors slam shut when you start the engine. How do they get up/open in the first place? Are you manually opening them? If so, then they should close when the engine is started(unless you have the over-ride knob pulled down, or the headlight switch on), so the "down" part is working.
I don't know which troubleshooting guide you have, but I have a couple of different ones, with diagrams, and such. I'd be happy to e-mail them if ya want. If all of the hoses are correctly positioned, and all of the vacuum relays are working, and the actuators are in good shape, then they should work correctly...but of course, they never do. I know of at least one vacuum diagram that has the hoses in the wrong location, too...
I can only suggest that you check and make sure the check valve is working, and your vacuum tank isn't leaking...



____________________________________
Joel Adams
C3VR Lifetime Member #56    
My Link


(click for Texas-sized view!)
             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
 Reply Reply  Quote Reply w/Quote
12/28/11 9:45pm - Reply: 'Re: Vacuum controls: headlight doors close but don't reopen on 68E'
theycallmered
Former Member
- Send Private Message


, - Australia

Vette(s):
Second-month production Shark, this 1968E was built up by original owner into 1969 ZR1 (L88 body with LT1 engine) for Club Racing. Body styling is from Maglioli's 1968 L88 "Le Mans" racer

Joined: 10/27/2010
Posts: 54
Joel's sent along some diagrams; thanks, Joel!  The diagram titled 'simplified' indicated that I had the hoses at the headlight switch reversed (from what is shown on Corvette Central's diagram for the 68E) but reversing them made no difference.  The 68E uses a single vacuum relay for both headlights, vs the pair used on later models.  So the typical diagram for 69 and later has to be 'interpreted'.

Later an accidental high rpm start broke free the wiper door when using the override valve; it now opens and closes freely even at low idle with the override valve.

And if I manually open the headlight doors, that override valve will close them (but not reopen them).

Easy to understand why kits offering to replace 'those troublesome vacuum headlights' have a market.  

I'll eventually get around to acquiring a vacuum test pump on eBay, locally they're very expensive; and use Joel's test regimen on each and every component.


|UPDATED|12/28/2011 6:45:44 PM (AZT)|/UPDATED|


____________________________________
1968E (2nd month production) convertible first registered California 1967 and a retired SCCA race car.  It is still race prepped and built up as a '69 ZR1 (announced '69 but not built until '70); i.e., the L88 car with LT1 motor.


 Reply Reply  Quote Reply w/Quote
12/28/11 11:41pm - Reply: 'Re: Vacuum controls: headlight doors close but don't reopen on 68E'
Adams' Apple Lifetime Member
Lifetime Member
Moderator
- Send Private Message


Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

Joined: 11/8/2003
Posts: 19449
My best guess would be that the headlight door relay is not functioning properly, since both doors will not open.

A hand-held vacuum pump will work, as will an air conditioning evacuation pump, if you can find one. I have both, but...they're easy to come by here.

Here's a Mityvac on ebay now for $5!
http://www.ebay.com/itm/Mighty-Vac-vacuum-pump-/160704722476?pt=Motors_Automotive_Tools&vxp=mtr&hash=item256abf762c




____________________________________
Joel Adams
C3VR Lifetime Member #56    
My Link


(click for Texas-sized view!)
             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
 Reply Reply  Quote Reply w/Quote
12/30/11 1:56pm - Reply: 'Re: Vacuum controls: headlight doors close but don't reopen on 68E'
F4Gary Gold Member
Gold Member
- Send Private Message


Grapevine, TX - USA

Vette(s):
1972 LT-1 convertible with factory air.

Joined: 8/26/2006
Posts: 862
Pulling down on the left manual knob should open them not close them.  Sounds like something is backwards.

____________________________________
 Reply Reply  Quote Reply w/Quote
 New Topic New Topic Post Reply Reply New Poll New Poll Search     Search Page [1]  
 Forums -> C3 Electrical
(Moderator: Adam Wartell, Norsky, Adams' Apple)
 

 
Official C3 Vette Registry Community:
Home | Forums | Email | Who's Online | Clubs | Events | Member Stats

Other Official C3 Vette Registry Areas:
Members | Research | Shop | My Account | About C3VR
 

Corvette is a registered trademark of the General Motors Corporation(GM) & Chevrolet Motor Division. Vette Registries, LLC is responsible for all site content (except for member submitted content or where otherwise noted) and does not claim or imply that Chevrolet or GM is responsible for Official C3 Vette Registry content. Vette Registries, LLC is independent from GM and is not affiliated with, sponsored or supported by GM.  Copyright/trademark/sales mark infringements are not intended, or implied and are in fact used to support GM, Chevrolet and Corvette

Official C3 Vette Registry content is Copyright 2001-2017, Vette Registries, LLC. Content may not be reused without written consent. All Rights Reserved. NS

Corvette (Vette) Model Years on this site: 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 30