Headlight switch question
I have my new headlight switch for my '73. Can't figure out how to mate the switch with the vacumn switch for raising and lowering the headlights. When I put the two together and turn the lights on, the headlights raise. However, when I turn the lights off, they don't retract.
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In Appreciation of John Hinckley -
Re: Headlight switch question
The headlight switch on the dash should have the vacuum switch built into it. If all is hooked up correctly, the headlights should go up and down as the lights are turned on and off.
Are you talking about the headlight vacuum override switch under the steering column? That is the only separate headlight vacuum switch I can think of. This switch, when pulled down, will cause the headlights to rise even when they are not lit. Pressing the switch upward should cause the lights to retract.
If the vacuum headlights are not behaving in the proper manner, a factory shop manual is invaluable in troubleshooting them. I believe some of the Corvette restoration vendors once had a small booklet dedicated just to the C3 vacuum system.Dave T.Comment
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Re: Headlight switch question
That's telling you there's a vac leak in the HL control circuit. The troubleshooting phamphlet Joe describes is an EXCELLENT tool for understanding how things work. But, here are the facts in a nutshell.
Vac comes from the intake and makes a 2-way split at the silver check valve in the engine compartment. The output of the check valve has one large nipple and one small nipple. The large nipple serves the vac servo system and routes to the vac storage tank in the engine compartment.
The small nipple serves the vac control system and a hose runs through the firewall and into the cockpit. Once in the cockpit, the control vac runs to the headlight over-ride switch (below the steering column), the across to the vac switch section that's part of the headlight switch.
From the headlight switch, the hose runs back out through the firewall and on to your headlight vacuum relay (nose of the car). It's this path that tells the headlights when to open/close.
The logic is venting vacuum in the cockpit (EITHER the headlight over-ride switch and/or the headlight switch) and the headlights will open. Close BOTH cockpit switches and let vac flow to the headlight relay in the nose of the car and the headlights will close.
So, the symptoms you describe indicate you've got a 'plumbing' problem in the cockpit that's allowing vac to vent in the dash. Either one or both control switches are faulty/leaking, OR you've got the vac hoses disconnected/mis-routed...Comment
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Re: Headlight switch question
I must have broke the switch without realizing it. I couldn't figure out how to keep the light switch and vacumn switch together. I even zip tied them together. Now that I look close at the light switch I can see a small tab broken , which is what must have held the switch and also caused the sliding motion of the vacumn switch.
Thanks for all the help.Comment
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