1975Coupe

Gents,

Question for you. Recently when I turn on my headlights the head lamps red light will turn on. I'm not sure what to look for. The headlights come up and turn on fine. So any thoughts?

ddawson

There is a little switch on each light that makes contact when the lights are up all the way.

theandies

One on each bucket.

Revi

If one switch isn't obviously broken(cracked, hanging, etc.), for trouble shooting purposes you can unplug them one at a time. When you unplug the bad one the red light will go out.

The switch could just be out of adjustment as well.

1975Coupe

Thanks guys. I'll take a look at it tonight and report back!

Alan 71

Hi 75,
There's a small button on the switch that the tab on the elbow depresses when the headlights are up.
You might check to see if the button is being depressed enough to cycle the switch.
Regards,
Alan

Sorry for the large size of the image. Photobucket is on the fritz!

Upper arrow is the 'tab'.
Lower arrow is the button.

1975Coupe

OK Newb question. How do you get to see that spot on the head lamp mechanism? Do you lie under the car? I tried turning them on when the car was idling and couldn't see anything from above or in front.

Alan 71

Hi 75,
NOT an easy place to see or REACH.
That photo is taken with the headlights raised and looking up from below through 1 of the 2 'breather' holes that 68-72 cars have in the lower valance.
Do 75s still have those holes?
Regards,
Alan

These 2 on 68-72 cars.

SwampeastMike

Until you know where to look they can be rather hard to see.

Nobody has yet suggested that you check to see if the warning light is doing what it is supposed to do--indicate when one or both headlights are not LOCKED into the "up" position. The actuator hyperextends the mechanism a bit--what I mean is that the last part its travel no longer raises the door; instead it locks the door into position so that vacuum is no longer required to keep it open.

A simple test is to turn off the engine with the headlamp switch "on" and the doors fully opened. Wait a few minutes. The doors should not drop in the least and a nice firm push should reveal that the door is physically locked into position.

If both are locked then your problem is most likely in the sensing circuit and also very likely to be a switch. If one or both is not locked however, the problem is within the headlamp door mechanism itself (this includes all of the vacuum components).

SwampeastMike

One other thing:

The headlamp doors make a quite loud "snap" sound as they lock into position. Unless your exhaust is extremely loud it's easy to hear them inside the cabin (open the windows).

theandies

I think the easiest way is to raise the headlamp buckets either with the switch or by hand (you can reach up and push up on the mechanism and they will open. Then take the trim pieces off from around the headlamps. On my '71 there are two screws on the sides at the back and two on the front edge above the lights. Once that is out of the way you can see the whole mechanism. As stated the hinge part of the open and close mechanism goes a little "over-center" to keep them up. Make sure this is adjusted correctly or the switch may or may not be depressed. The switch is in that location as shown in Alan's photos.

When I bought my car one of the switches was broken off where it screws into the mechanism. It's just plastic threads that hold it in. My light was always on until I figured it out. I put a tie-wrap on the broken switch to depress it until I got a replacement.

1975Coupe

I can easily hear them snap. However when I turn off the engine the headlamps go back into the body, even if I've left them in the on position. So does that mean I have an issue with the mechanism since they aren't locking into place?

SwampeastMike

Yes, it sounds to me like there is some issue with the mechanism as they should stay up forever after you stop the engine. Worn bushings and/or bearings could, I suppose, cause enough slop in the mechanism that even though you hear the "snap" they still aren't locking.

Alan 71

Hi 75,
What happens when you open the headlight doors using the vacuum override switch with the engine running and then shut the engine off?
Regards,
Alan

1975Coupe

No idea. Where is the vacuum override switch and how do I use it?

Alan 71

Hi 75,
The headlight vacuum override is located below the steering column.
When yo pulo down on it the headlights open and stay up regardless of the position of the headlight switch.
Regards,
Alan

This is from a 71 so has a control for the wiper door too.

1975Coupe

Mine doesn't have that. I don't have a pic from below but I don't have three switches/***** on the bottom of my steering wheel.

Alan 71

Hi 75,
I believe all 68-82 had the vacuum over-ride switch for the headlight vacuum system.
It's necessary for instance, to hold the doors open in order to change a headlight bulb.
It sounds like someone has by passed it.
Look for 2 hoses with not connected to anything or 2 joined by some sort of connector.
Regards,
Alan

This is the vacuum switch and 2 hoses hoses.
Since yours is missing it appears someone has been playing with the vacuum system.