How do these Headlights work?? 1975
Thread Starter
Racer
Joined: Jul 2005
Posts: 317
Likes: 0
From: PA
How do these Headlights work?? 1975
How exactly do these work?? If I suck in the vac lines to the actuators should something happen? I can't get the lights to go down. There are two wires that go to an arm on the underside of the lights when they're in the up position, what are they?? Please Help!!!
Le Mans Master
Joined: Mar 2001
Posts: 6,640
Likes: 287
From: Ann Arbor Michigan
I'm not sure about 75', but on my 71', the switch is for a red light on the dash that tells you if the doors didn't open when the headlight switch is pulled. If you pull a vacuum on the actuator can, the lights should open or close depending on which port you apply vacuum. Hope this helps.
Racer
Joined: Jan 2003
Posts: 383
Likes: 0
From: Columbia SC
Dont worry about the 2 wires going to a switch under the locking arm. Thats not the problem.
You could have no vac going to the front of the car or one (or both) of the control valves may be shot.
If you apply vac from a hand pump to each control valve you can troubleshoot them one at a time.
You could have no vac going to the front of the car or one (or both) of the control valves may be shot.
If you apply vac from a hand pump to each control valve you can troubleshoot them one at a time.
Burning Brakes
Joined: Dec 2004
Posts: 918
Likes: 5
From: Gainesville FL
What were the symptoms? Did the lights work until recently or is this a new (to you) car? The relays are the most common problem area with actuator seals following closely behind as culprits. If the car is new to you, I would disconnect the hoses at the relay and make sure that the mechanisms move freely. To get them to go down manually, you have to reach from underneath the car and pull the linkage down and toward the front so that the "knee" unlocks (don't just push down on the doors from above). If they pass this test, hook a hand vacuum pump to each actuator hose and pull a vacuum and see what happens. This will get you started and see whether the actuators are the problem or not.
Thread Starter
Racer
Joined: Jul 2005
Posts: 317
Likes: 0
From: PA
Yes the car is new to me, the lights were up when I got it, the actuators seem to be in good shape, ie. clean. I took the vac lines off of both actuators and sucked on them as hard as I could ( I know how that sounds HA) , they don't leak and I heard a click but nothing happens. Where do I find the relays??
Burning Brakes
Joined: Dec 2004
Posts: 918
Likes: 5
From: Gainesville FL
The relays hang from the top of the body just in front of the hood. One is near the center of the car, the other is nearby toward the right. They will each have four vacuum hoses going into them (one small and three large). You will probably have to have a hand vacuum pump to get any movement from the actuators. I have downloaded several good papers referenced in this forum for testing and troubleshooting the headlight system. Unfortunately, I can't seem to find them right now, but a search of the archives should turn them up. Alternatively, send me a PM and I will e-mail them to you.
Le Mans Master
Joined: Jun 2004
Posts: 9,289
Likes: 16
From: Skippack PA
St Jude Donor '13
http://209.183.231.72/corvette-101/vacuum.htm
There are vacuum connections on the front and the back of the actuators. One side closes, one side opens. If nothing happens when you apply vacuum to either of these ports then the diaphragm in the actuator is likely shot and either needs to be rebuilt or simply replace the actuator.
For example, when applying vacuum to the "back" connection (nearest the engine) my headlight would go down. But when applying vacuum to the front port the headlight would not go up. Per the troubleshooting guide from that link above this meant the diaphragm was ok, but the seal on the actuating rod was bad. I bought the $20 "witches hat" kit and replaced the seal and BINGO!
Hope this info helps.
There are vacuum connections on the front and the back of the actuators. One side closes, one side opens. If nothing happens when you apply vacuum to either of these ports then the diaphragm in the actuator is likely shot and either needs to be rebuilt or simply replace the actuator.
For example, when applying vacuum to the "back" connection (nearest the engine) my headlight would go down. But when applying vacuum to the front port the headlight would not go up. Per the troubleshooting guide from that link above this meant the diaphragm was ok, but the seal on the actuating rod was bad. I bought the $20 "witches hat" kit and replaced the seal and BINGO!
Hope this info helps.
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Safety Car
Joined: Nov 2003
Posts: 4,273
Likes: 1
From: Pittsford NY
Perhaps somebody mentioned it and I missed it but there
is a manual over ride switch. (At least on my 74). It is
under the dash roughly under the steering wheel. Up headlights
come up when you turn the lights on and down when you
turn them off. Switch down headlights up all the time.
This is assuming my memory is correct.
is a manual over ride switch. (At least on my 74). It is
under the dash roughly under the steering wheel. Up headlights
come up when you turn the lights on and down when you
turn them off. Switch down headlights up all the time.
This is assuming my memory is correct.
