Help! Help! Help!
Thread Starter
5th Gear
Joined: Sep 2014
Posts: 5
Likes: 0
Help! Help! Help!
I am working on my buddies 74 corvette (c3) and we have a concern. The headlights go up at the same time in the first try but if you pull the headlight switch the second time right after the previous pull,the driver side head light goes up and the passenger head light delays 3 seconds and then goes up.Is this normal???
Team Owner
Joined: Sep 2006
Posts: 31,269
Likes: 4,362
From: Westminster Maryland
Hi ette,
Sorry to disagree but it's not 'normal'.
If the engine is running they should continue to open and close in unison.
If the right side doesn't move for 3 seconds, and then opens quickly, it's likely a problem with the relay for that actuator. (1 or 2 relays in 74?)
If it begins to open immediately, but opens slowly, it's likely a problem with a leak in the 'open' side of the actuator.
Also check that the vacuum reservoir tank doesn't have a leak.
Regards,
Alan
Sorry to disagree but it's not 'normal'.
If the engine is running they should continue to open and close in unison.
If the right side doesn't move for 3 seconds, and then opens quickly, it's likely a problem with the relay for that actuator. (1 or 2 relays in 74?)
If it begins to open immediately, but opens slowly, it's likely a problem with a leak in the 'open' side of the actuator.
Also check that the vacuum reservoir tank doesn't have a leak.
Regards,
Alan
Melting Slicks
Joined: Apr 2007
Posts: 3,189
Likes: 111
From: Tolland CT
Does it behave this way if you open the head lights, then close and wait 30 seconds or more before reopening? If waiting helps I'd suspect you have a vacuum leak, taking more time for the vacuum reservoir (tank) to replenish. I found I had several leaks on my 70, most were from the vacuum relays. To find them I used a hand held vacuum pump with a gauge to test for leaks at the various components. After replacing the three vacuum relays (70 has three) my headlights became very responsive. Hope this helps. 
Last edited by BBCorv70; Sep 30, 2014 at 12:56 PM.
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From: New Or-leens Loo-z-anna
ettevroccorvette!
Do you realize the second half of your Username is written backwards?
(Yes.....I have dyslexia.....LoL)
Hang in there.....you'll solve all the problems.
Do you realize the second half of your Username is written backwards?
(Yes.....I have dyslexia.....LoL)
Hang in there.....you'll solve all the problems.
Burning Brakes
Joined: May 2014
Posts: 1,094
Likes: 16
From: Los Angeles California
I saw the name and didn't catch it I was still trying to pronounce it 
But I consider it normal at least on my rig but I don't care to fix it as im looking for the perfect lights to use as FIXED lights
But I consider it normal at least on my rig but I don't care to fix it as im looking for the perfect lights to use as FIXED lights
Melting Slicks
Joined: Apr 2007
Posts: 3,189
Likes: 111
From: Tolland CT
Did that solve your problem? If not I'd guess you have other leaks. I tracked mine down using a handheld vacuum pump with a gauge, used for bleeding brakes. I isolated portions of the plumbing by pinching off the hose, see if it could hold a vacuum. Moved down the line until I found a section which leaked. Could be a leaky vacuum tank?