77 headlight issue
Thread Starter
Intermediate
Joined: Jun 2012
Posts: 31
Likes: 0
From: Braintree MA
77 headlight issue
having a little issue with the headlights on my 77. Going to spend the day tomorrow checking everything over but wanted to see if anyone here had run into this and might be able to point me in the right direction.
if i turn the headlights on they come up like normal. but lately when i shut them off they stay up. if i turn the car off wait a second and start it back up they drop back down again.
anyone run into this before? pretty much was just going to trace the whole vacuum system back and see if i found anything.
if i turn the headlights on they come up like normal. but lately when i shut them off they stay up. if i turn the car off wait a second and start it back up they drop back down again.
anyone run into this before? pretty much was just going to trace the whole vacuum system back and see if i found anything.
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From: Jeffersonville Indiana 812-288-7103
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For the headlamps to stay up the vacuum must be blocked on the black hose with the white stripe running to the headlamp actuator.
Check for a loose, cracked or missing hose and then check these items.
To avoid a run through the car.. go to the headlamp relays.. with the switch off, pull the black with a white stripe hose off one and see if you have vacuum. If you do not then you need to find out why you don’t have it. If you do, then should test the relay to see if it is working. You find out how to test the relays here:
If you don’t have vacuum on the black/white hose then something is blocking it…
With the lamp switch off.
Go to the small hose side of the check valve, pull off the hose and see if you have vacuum there. If you do great if not then replace the filter.
Next I would go to the hose on the bottom of the over-ride switch; this is the one closest to the **** (lower one). It should have a blue stripe on it. Go to this and see if you have vacuum with the lamp switch off. If you do, pull the headlamp **** out and see if you drop the vacuum. If you drop vacuum you have verified the lamp switch is working fine. If you don't you need a lamp switch for sure but you have not found the issue.
So.. if you have vacuum on the blue stripped hose at the over-ride then plug it back in and move on…
If the issue is not on the small side then you need to look at the reservoir and the actuators to see if they are working properly. Again you can find a test on that in the above video.
Willcox
Check for a loose, cracked or missing hose and then check these items.
To avoid a run through the car.. go to the headlamp relays.. with the switch off, pull the black with a white stripe hose off one and see if you have vacuum. If you do not then you need to find out why you don’t have it. If you do, then should test the relay to see if it is working. You find out how to test the relays here:
If you don’t have vacuum on the black/white hose then something is blocking it…
With the lamp switch off.
Go to the small hose side of the check valve, pull off the hose and see if you have vacuum there. If you do great if not then replace the filter.
Next I would go to the hose on the bottom of the over-ride switch; this is the one closest to the **** (lower one). It should have a blue stripe on it. Go to this and see if you have vacuum with the lamp switch off. If you do, pull the headlamp **** out and see if you drop the vacuum. If you drop vacuum you have verified the lamp switch is working fine. If you don't you need a lamp switch for sure but you have not found the issue.
So.. if you have vacuum on the blue stripped hose at the over-ride then plug it back in and move on…
If the issue is not on the small side then you need to look at the reservoir and the actuators to see if they are working properly. Again you can find a test on that in the above video.
Willcox
Last edited by Willcox Corvette; Sep 14, 2012 at 05:30 PM.
Thread Starter
Intermediate
Joined: Jun 2012
Posts: 31
Likes: 0
From: Braintree MA
Thanks for the info, still havent got it traced down yet but between that diagram and your video i'm pretty sure i can get it straightened out.
For the headlamps to stay up the vacuum must be blocked on the black hose with the white stripe running to the headlamp actuator.
Check for a loose, cracked or missing hose and then check these items.
To avoid a run through the car.. go to the headlamp relays.. with the switch off, pull the black with a white stripe hose off one and see if you have vacuum. If you do not then you need to find out why you don’t have it. If you do, then should test the relay to see if it is working. You find out how to test the relays here:
If you don’t have vacuum on the black/white hose then something is blocking it…
With the lamp switch off.
Go to the small hose side of the check valve, pull off the hose and see if you have vacuum there. If you do great if not then replace the filter.
Next I would go to the hose on the bottom of the over-ride switch; this is the one closest to the **** (lower one). It should have a blue stripe on it. Go to this and see if you have vacuum with the lamp switch off. If you do, pull the headlamp **** out and see if you drop the vacuum. If you drop vacuum you have verified the lamp switch is working fine. If you don't you need a lamp switch for sure but you have not found the issue.
So.. if you have vacuum on the blue stripped hose at the over-ride then plug it back in and move on…
If the issue is not on the small side then you need to look at the reservoir and the actuators to see if they are working properly. Again you can find a test on that in the above video.
Willcox
Check for a loose, cracked or missing hose and then check these items.
To avoid a run through the car.. go to the headlamp relays.. with the switch off, pull the black with a white stripe hose off one and see if you have vacuum. If you do not then you need to find out why you don’t have it. If you do, then should test the relay to see if it is working. You find out how to test the relays here:
If you don’t have vacuum on the black/white hose then something is blocking it…
With the lamp switch off.
Go to the small hose side of the check valve, pull off the hose and see if you have vacuum there. If you do great if not then replace the filter.
Next I would go to the hose on the bottom of the over-ride switch; this is the one closest to the **** (lower one). It should have a blue stripe on it. Go to this and see if you have vacuum with the lamp switch off. If you do, pull the headlamp **** out and see if you drop the vacuum. If you drop vacuum you have verified the lamp switch is working fine. If you don't you need a lamp switch for sure but you have not found the issue.
So.. if you have vacuum on the blue stripped hose at the over-ride then plug it back in and move on…
If the issue is not on the small side then you need to look at the reservoir and the actuators to see if they are working properly. Again you can find a test on that in the above video.
Willcox
