Headlight vacuum system
Thread Starter
Burning Brakes
Joined: Nov 2005
Posts: 924
Likes: 15
From: DFW Metroplex Texas
Headlight vacuum system
Symptoms:
1. Lights will not raise or lower when engine is off.
2. Lights will raise out of sync.
a. Left opens all the way and locks.
b. Right opens most of the way but will not open to extent to lock.
I started trouble shooting today and found one very loose hose connection at the check valve.
Since I have no vacuum when the engine is off, I inspected the check valve (the one with 3 nipples) and discovered that air could flow freely in both directions.
Is it probable that when I replace the check valve that would fix my headlight operation or should I look a little deeper?
Any suggestions appreciated
Tex
1. Lights will not raise or lower when engine is off.
2. Lights will raise out of sync.
a. Left opens all the way and locks.
b. Right opens most of the way but will not open to extent to lock.
I started trouble shooting today and found one very loose hose connection at the check valve.
Since I have no vacuum when the engine is off, I inspected the check valve (the one with 3 nipples) and discovered that air could flow freely in both directions.
Is it probable that when I replace the check valve that would fix my headlight operation or should I look a little deeper?
Any suggestions appreciated
Tex
Burning Brakes
Joined: Jun 2002
Posts: 837
Likes: 3
From: Texas
I would start with the check valve. Slightly out of sync is pretty common.....not a big worry. You may have a problem with the right side.....either relay or shaft seal on the actuator.
Down in Ellis county here if I can be of more help.
Down in Ellis county here if I can be of more help.
Drifting
Joined: Sep 2004
Posts: 1,270
Likes: 4
From: Celeste Texas
1. Lights won't open with the engine off.
2. They rarely come up together.
3. Once the right light has started moving GENTLY push it up the rest of the way to make sure it will go. Look up from underneath and make sure nothing is blocking travel.
I'm right up the road in McKinney and I don't mind helping if you have other problems.
Bill
2. They rarely come up together.
3. Once the right light has started moving GENTLY push it up the rest of the way to make sure it will go. Look up from underneath and make sure nothing is blocking travel.
I'm right up the road in McKinney and I don't mind helping if you have other problems.
Bill
Instructor
Joined: Jun 2005
Posts: 122
Likes: 0
From: Rochester MN
My guess is you don't have enough vacuume flow. I had the same problem with mine. Then one day they just didn't move. I had to follow the line from the carb to the headlight until I found a leak. It was in a spot close to the valve cover/exhaust manifold. Now they go up and down at about the same time. They don't need to be in perfect sync. Even a 747 starts its jets at different times!!! 
Thread Starter
Burning Brakes
Joined: Nov 2005
Posts: 924
Likes: 15
From: DFW Metroplex Texas
Thanks for input all!
I ordered a check valve yesterday since I know it is bad. These are the original hoses so I do need to conduct a closer inspection of all connections.
Have a great Thanksgiving.
Let the Football games start!
I ordered a check valve yesterday since I know it is bad. These are the original hoses so I do need to conduct a closer inspection of all connections.
Have a great Thanksgiving.
Let the Football games start!
Race Director
Joined: Feb 1999
Posts: 19,659
Likes: 34
From: Lenoir City Tennessee
Ci 6, 8 & 10 Veteran
St. Jude Donor '05-'06-'07-'08-'09-'10-'11-'12-'13-'14-'15
http://www.corvette-101.com/
Follow this link on how to troubleshoot your headlight problem. When the page opens up, look for the link on the left side Vaccum Trouble. He gives pretty good info on how to troubleshoot each component to be sure it is or is not working correctly. Good info on the check valve also.
Follow this link on how to troubleshoot your headlight problem. When the page opens up, look for the link on the left side Vaccum Trouble. He gives pretty good info on how to troubleshoot each component to be sure it is or is not working correctly. Good info on the check valve also.
Thread Starter
Burning Brakes
Joined: Nov 2005
Posts: 924
Likes: 15
From: DFW Metroplex Texas
Originally Posted by Eddie 70
I would love to fix this myself without taking it into a shop
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Melting Slicks
Joined: Mar 2002
Posts: 2,140
Likes: 7
From: Ohio
Get a long small hose from the hardware store. Get vacumn from a running car outside garage and hook to main hose. Now that motor is not running you should hear the leaks. The relay valves is what I find bad the most.