Head light covers wont close

[1978LincolnSpecial]

I went to my car today and usedthe headlights in the morning when i went to turn them off the switch wasnt buzzing to let me kn ow the headlights were still on when i turned the key off and then i realized i lost some kind of power to the switch now they are stuck in the open position how can i fix this myself?


Thanks any help is appreciated:(

[Dereck]

Hi 1978LincolnSpecial

Do the headlights still work?

The headlight doors are vacuum operated and default to open when they lose vacuum.

Could be one of several faults;

1 Vacuum leak (Do they close with the engine running?)
2 Vacuum not getting switched by the main light switch.
3 Vacuum not getting switched by the autolamp vacuum relay.
4 Vacuum check valve stuck closed allowing no vacuum to build
5 Pipe blockage

You could try giving the main light switch a bit of a jimmy with the engine running see if the doors close after that you will have to play follow the vacuum.

I would start by checking the vacuum check valve isnt stuck closed, it is a a little sivler disc like thing with a pipe coming out of the top and bottom on the back of the intake usually in a pipe with an orange stripe.

Regards

Dereck

[1978LincolnSpecial]

Yes the headlights work fine, but i have no vacum so they wont close where do i look for that under the hood?

I am still learning my grandpas girl now my lady ive done a lot of work already but still learning can you explain how or where i start?


Thanks

[ImTheJoker4u2]

Yes the headlights work fine, but i have no vacum so they wont close where do i look for that under the hood?

I am still learning my grandpas girl now my lady ive done a lot of work already but still learning can you explain how or where i start?


Thanks

Vacum is usually obtained by tapping into the intake (the piece directly under the carb.) My guess on an older vehicle like that, the vacum lines are shot. Most auto parts stores carry an assortment of tubing. Like I said the car is old..I would replace all the lines and see if the problem persists. If it doesnt fix this specific problem, at least you'll know that youve done some needed and often overlooked maintenance.;)

[1978LincolnSpecial]

Thanks right on dude i will do that tomorrow it just dont loook right with the covers up when not in use ill go to auto zone after i cheack the intake thanks for the help:o

[Dereck]

Hi

Replacing the vacuum lines isn't as easy as it sounds, there are miles of them for the headlight doors.

Usually the doors will close with the engine running even if there is a vacuum leak, a leak big enough to keep the doors open would most likely cause poor running engine problems, especially at idle.

At the moment I am leaning towards the autolamp vacuum switch stuck keeping the doors open.

Regards

Dereck

[95pres]

+1 for autolamp switch.
If you turn the lights on and off (with engine running) and DON''T hear a slight (very quiet) hissing/sucking sound from inside the dash when turning them off, you'll be one step closer to finding the problem.
just trace the line(s) from dash switch to intake, you should run into you problem along the way. If you do hear a hissing sound, follow the line to the headlight vaccum cans.

FYI- when checking for vaccum leaks, you can spray each line with carb cleaner (with engine running)- if the engine surges (approx.100-150rpm), you've found a vaccum leak. works great for about 90% of vaccum leaks
-I know this is an old trick, but figured it's one worth mention.

But as Dereck mentioned, it's doubtful that you have just a 'leak', sounds more like something just stopped working.

Good luck- Brad