72 vac line question
Thread Starter
Melting Slicks
Joined: Feb 2006
Posts: 2,092
Likes: 5
From: Fayetteville Arkansas
72 vac line question
SO here's a thought I was having last night while laying awake and wishing I had had more time over the weekend to do things like work on my cars....
My headlights stay up at all times... it doesn't matter if the car is on or off. If the car is off and I manually put the lights down they stay down until I start the car and then they will pop right back up. While the car is on they stay up no matter what I do. So here is my question...since I dont have a vac line pressure tester or anything, for testing the headlight switch can I remove the two lines from it and then plug them together? wouldn't that cause them to close if the headlight switch isn't working right? or if the problem is at the over ride switch can I just pull those lines off and plumb them together? Just to test the switch and not, not permanent or anything? I am thinking in the right direction?
thanks,
Sully
My headlights stay up at all times... it doesn't matter if the car is on or off. If the car is off and I manually put the lights down they stay down until I start the car and then they will pop right back up. While the car is on they stay up no matter what I do. So here is my question...since I dont have a vac line pressure tester or anything, for testing the headlight switch can I remove the two lines from it and then plug them together? wouldn't that cause them to close if the headlight switch isn't working right? or if the problem is at the over ride switch can I just pull those lines off and plumb them together? Just to test the switch and not, not permanent or anything? I am thinking in the right direction?
thanks,
Sully
Advanced
Joined: Jun 2008
Posts: 58
Likes: 1
From: Eastampton NJ
Its a complicated system. Assuming "Bubba" hasn't been working on your headlight door system, it sounds from your description that at least half of the system is in place (maybe!) and the problem is in the control-half of the system. The control vacuum path is a) engine compartment to b) headlight switch to c) override switch to d) vac relays (between headlights). With the engine running, pull the hoses off the override switch (under the steering column). With the headlight switch in you should have vacuum on the hose with the blue stripe. Pull a vacuum with your mouth on the other hose (its like sucking a milkshake through a straw) & the headlights should close. If either side isn't as I've said, work on that side...
Thread Starter
Melting Slicks
Joined: Feb 2006
Posts: 2,092
Likes: 5
From: Fayetteville Arkansas
Its a complicated system. Assuming "Bubba" hasn't been working on your headlight door system, it sounds from your description that at least half of the system is in place (maybe!) and the problem is in the control-half of the system. The control vacuum path is a) engine compartment to b) headlight switch to c) override switch to d) vac relays (between headlights). With the engine running, pull the hoses off the override switch (under the steering column). With the headlight switch in you should have vacuum on the hose with the blue stripe. Pull a vacuum with your mouth on the other hose (its like sucking a milkshake through a straw) & the headlights should close. If either side isn't as I've said, work on that side...
Sully
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
thanks for the details... I do have Doc Rebuild's vac hose diagram and it has helped with finding all the routing so far. I double checked and all the hoses up front at the relays and actuators are correctly routed. Last night I turned the car on and with the engine running applied vacuum to the blue striped hose at the headlight switch and the headlights went down. So now I am guessing that something has come loose on the line coming from the vac check valve where it splits to go to the wiper solenoid behind the tach. Does that sound abotu right to you guys?
Sully
Sully
So when you say you applied vacuum to the blue hose-that means the vacuum went down through the pulldown and out to the relays.Correct?
If so the other hose on the headlight switch the white striped one-did it have vacuum on it ?
EDIT-just reread your OP thats a good idea to put the 2 hoses together at the headlight switch-if the lights go down the the headlight switch is bad.
Last edited by ...Roger...; Jun 24, 2008 at 09:53 AM.
Thread Starter
Melting Slicks
Joined: Feb 2006
Posts: 2,092
Likes: 5
From: Fayetteville Arkansas
Sounds like your on the right track.
So when you say you applied vacuum to the blue hose-that means the vacuum went down through the pulldown and out to the relays.Correct?
If so the other hose on the headlight switch the white striped one-did it have vacuum on it ?
EDIT-just reread your OP thats a good idea to put the 2 hoses together at the headlight switch-if the lights go down the the headlight switch is bad.
So when you say you applied vacuum to the blue hose-that means the vacuum went down through the pulldown and out to the relays.Correct?
If so the other hose on the headlight switch the white striped one-did it have vacuum on it ?
EDIT-just reread your OP thats a good idea to put the 2 hoses together at the headlight switch-if the lights go down the the headlight switch is bad.
sully
