74 Headlight vacuum issues...HELP

[igasper10]

Ok, i've read up on all the tests for this finicky vacuum system for our headlights and performed them all. My lights pop up as soon as I start the engine! My actuators are good (tested), both relays are brand new, override switch is good (tested). When I kill the engine, the lights stay up but push down manually easily (no pressure keeping them up after shut-down). So then I pull down my override thinking they'll come back up like they're supposed to......wrong........ what would cause this???

ian ;help

 

[Bob Chadwick]

Are you saying that when there is no vacuum the headlights don't go down? That's the way they are supposed to work. Mine will go down for about 10 seconds after I turn the car off but that is about it.

There is a vacuum canister that "holds" vacuum to operate the accessories during periods of low vacuum but after all these years the system probably leaks enough that that is the best I can expect. I don't know how long it held new.

There is actually a check valve and filter right near the carb where the vacuum comes out. I replaced both, with the check valve making a significant improvement.

 

[Red76Vette]

Its probably a loose hose or bad connection like c5d said if you cant find it just go with killer lights system looks to be the best thing since fixed lights. They are kind of pricy but well worth it if you have the cash to spend!!! Killer lights

Late,
Chuck

 

[igasper10]

No, when there IS vacuum that should pull the lights down, they go up. Thus, when I first start the engine, with the light switch off, the headlights immediately go up. The switch has no effect on or off. Maybe a bad switch?

ian

 

[igasper10]

PROBLEM SOLVED

I pulled the dash panel off and discovered one of the lines was disconnected at the switch. Hooked it back up and everything works great now! Thanks for the suggestions all...

ian