L Holmes

I have a 1970 LT-1 Car and all my fiber optic light monitoring system still works but the other day the HEADLIGHT red indicator next to the gauges & the seat belt light came on and the fiber optic monitoring system indicated I had a high beam out on the drivers side. I looked and sure enough the bulb was bad. I replaced the bulb and its working now but both my indictors are still indicating the headlight is still out?? Any ideas?

Easy Mike

Fiber optics is a standed plastic material which conducts light. It is completely inert and has no power on it's own. Light shining through one end passes down the cable to the other end.

The FO high beam indicator is part of the plug on the rear of the head light capsule. Older capsules emitted a small amount of light at the rear which the FO picked up. Newer capsoules do not emit light at the rear. Without a light source, the FO appears not to be working.

jeffstuarts

The red light only indicates that the headlamp assembly is not in the full up and locked position. There is a switch that in there that is normally closed and is opened when the door is fully open. If this light stays on and the assembly IS up and locked, either the wire to the switch is broken or the switch itself is broken which is normally the case. It is ABS plastic and, with age, becomes brittle and breaks. If this is the case you will find it hanging by the wires. If you look at the back of the headlight bulb, you will see a "nipple" at the center of the prongs. This needs to be clear glass. some of the bulbs are painted black. This is the source of the light to the fiber optics. I haven't looked for a long time but I would bet you can find both at your local parts store. Hope this helps.
Jeff

L Holmes

Outstanding. thanks

L Holmes

Anyone have a picture or a part number for this limit switch? thanks

jnealg

L Holmes

Thank you.

Alan 71

Hi LH,
Here's the headlight warning switch installed.
It has nothing to do with the satisfactory operation of the fiber-optics.
It's purpose (as Jeff said) is only to warn that the headlights lights are on until the headlight door is fully open. It's normally on for only a half a second while the headlight doors open.
A tab on the headlight mechanism pushes the button on the switch when the door is fully open.
The button has a tiny rubber boot on it to protect it. Make sure the button is free to move and the tab pushes the button in far enough.
Regards,
Alan

L Holmes

Ah yes, I have seen that switch before thanks Alan. I am at work now but when I get home tonight I will inspect the switch / connection. Thanks so much for taking the time to post that picture, I will know right where to go looking now.
I always get really good help from the people who use this forum. Thanks again

L Holmes

I knew I should have dug out one of those old T-3 headlights I have stockpiled. I must have 20 or 30 of them but I bought a new bulb on the way home from work the other day and just use it instead.. When I was a teenager I used to go thru ALL the local junkyards with and OHM meter and test any T-3 headlights & if I found good ones I would bring them home.