Headlights come up when engine is started...
Thread Starter
Cruising
Joined: Oct 2024
Posts: 14
Likes: 1
From: SE Wisconsin
Headlights come up when engine is started...
Headlights come up when engine is started WITHOUT the headlight switch being activated...
Of course, they wont go back down on their own at any time.
The "pull down" rod under the steering column is in the up position (non activated).
I'm guessing one or more of the vacuum lines is incorrectly routed...
What says the brain trust??
Does the center counsel need to be removed (with side panels and carpet section) to replace the fan blower switch??
Thanks in advance!!!
Of course, they wont go back down on their own at any time.
The "pull down" rod under the steering column is in the up position (non activated).
I'm guessing one or more of the vacuum lines is incorrectly routed...
What says the brain trust??
Does the center counsel need to be removed (with side panels and carpet section) to replace the fan blower switch??
Thanks in advance!!!
Melting Slicks
Joined: Apr 2021
Posts: 2,718
Likes: 2,163
From: Minnesota
Welcome to the forum!
I would trace the vacuum lines from the headlights in the engine bay to make sure the switch hasn’t been bypassed. Unless this is a new issue.
Not sure about a 78’, but in my 76’ I only need to remove the center console metal plate to gain access to the fan controls.
I would trace the vacuum lines from the headlights in the engine bay to make sure the switch hasn’t been bypassed. Unless this is a new issue.
Not sure about a 78’, but in my 76’ I only need to remove the center console metal plate to gain access to the fan controls.
Thread Starter
Cruising
Joined: Oct 2024
Posts: 14
Likes: 1
From: SE Wisconsin
Thanks for the quick replies!!
Car is new to me, so I'm figuring out a lot of issues (minor) with it. Have most of them figured out and it drives great...
Have a solid mechanical background so that helps a lot...
Theandies: Where is the check valve located?? might as well start with the easy stuff!!!
TIA!!
Car is new to me, so I'm figuring out a lot of issues (minor) with it. Have most of them figured out and it drives great...
Have a solid mechanical background so that helps a lot...
Theandies: Where is the check valve located?? might as well start with the easy stuff!!!
TIA!!
Race Director
Joined: Mar 2017
Posts: 11,953
Likes: 4,510
From: Virginia
Here's the long answer:
https://www.corvette-101.com/vacuum.htm
Here's the shortcut (Made in USA!):
https://www.ebay.com/str/richard454
https://www.corvette-101.com/vacuum.htm
Here's the shortcut (Made in USA!):
https://www.ebay.com/str/richard454
Instructor
Joined: Dec 2020
Posts: 190
Likes: 54
From: Northern VA
I am sort of getting the same thing, however my headlights "cycle" occasionally. My wiper door "cycles" every time I start the car. The headlights immediatly go back down as does the wiper door once the car has run for a few seconds.
I have replaced the relays in both recently, I have a feeling it is about the cheap chinese relays and losing vacuum pressure overnight or over a couple of days of not being run - thats when the headlights seem to cycle.
OR - do I have a leak somewhere.
'69 - 427 - 390 with AC....
I have replaced the relays in both recently, I have a feeling it is about the cheap chinese relays and losing vacuum pressure overnight or over a couple of days of not being run - thats when the headlights seem to cycle.
OR - do I have a leak somewhere.
'69 - 427 - 390 with AC....
Last edited by HCK; Oct 22, 2024 at 04:16 PM.
Burning Brakes
Joined: Dec 2005
Posts: 1,153
Likes: 341
Tips on vacuum controlled headlights / wiper door
Here's the grandmother of all articles on diagnosing the vacuum system in a C3. I posted it over on Reddit as it allowed me to post more pictures,
GL
https://www.reddit.com/r/Corvette/co...en_headlights/
GL
https://www.reddit.com/r/Corvette/co...en_headlights/
Instructor
Joined: Dec 2020
Posts: 190
Likes: 54
From: Northern VA
Here's the grandmother of all articles on diagnosing the vacuum system in a C3. I posted it over on Reddit as it allowed me to post more pictures,
GL
https://www.reddit.com/r/Corvette/co...en_headlights/
GL
https://www.reddit.com/r/Corvette/co...en_headlights/
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Drifting
Joined: Nov 2002
Posts: 1,787
Likes: 261
From: Blue Bell PA
2018 C3 of Year Finalist
This is the best article I have ever seen on the subject. Going to join Reddit so I
can find this again. Thanks. I found going to eBay and finding old parts works better.
can find this again. Thanks. I found going to eBay and finding old parts works better.