1955 Headlight help

Started by 55 ledsled, March 24, 2019, 05:09:07 PM

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55 ledsled

Hey everyone, hoping that you could help me. I had the front of my 55 sedan apart and now its back together. I have no functional headlights/fog lights but my tail lights work. I have a yellow wire coming off of the wire harness (drivers side) somewhat near the heater blower motor with about a 1/4" eyebolt wire connector on the end of it, and the wire is about 8" long off of the harness. I can't figure out where the hell it goes lol. I threw a meter on it and it shows 12v power when I pull the headlight switch out so I am guessing that's my problem. Everything is factory (no wire mods) and the guts of the eye controller seem to warm up as checked with a laser thermometer. Any ideas of where that yellow wire goes so that I can get my lights working again? Thanks!

J. Gomez

Quote from: 55 ledsled on March 24, 2019, 05:09:07 PM
Hey everyone, hoping that you could help me. I had the front of my 55 sedan apart and now its back together. I have no functional headlights/fog lights but my tail lights work. I have a yellow wire coming off of the wire harness (drivers side) somewhat near the heater blower motor with about a 1/4" eyebolt wire connector on the end of it, and the wire is about 8" long off of the harness. I can't figure out where the hell it goes lol. I threw a meter on it and it shows 12v power when I pull the headlight switch out so I am guessing that's my problem. Everything is factory (no wire mods) and the guts of the eye controller seem to warm up as checked with a laser thermometer. Any ideas of where that yellow wire goes so that I can get my lights working again? Thanks!

Adam,

You do not mention if you have the Autronic-eye option on yours. ???

The only “yellow” wire was with that option coming from the footswitch from the Autronic-eye hardness to a “ground” from the power relay (see autronic-eye wiring -> http://forums.cadillaclasalleclub.org/index.php?topic=149817.0;topicseen).

If yours was removed and converted to a non-autronic-eye the “light blue” wire from the headlight switch will go over to the footswitch “BATT” and the main “dark green” and “tan” from the headlights hardness would go to “1” and “2” on the footswitch.

You may need to trace around the driver side hardness and see if those two wires from the headlight are and what other are coming from the footswitch.

Geed luck..!
J. Gomez
CLC #23082

55 ledsled

Yes it has the Eye and everything is stock. I doubt it is a ground as it has 12V power to it and I can turn it off with the headlight switch. The eyebolt crimped on the end has to go somewhere. Thanks

J. Gomez

Quote from: 55 ledsled on March 25, 2019, 10:24:17 AM
Yes it has the Eye and everything is stock. I doubt it is a ground as it has 12V power to it and I can turn it off with the headlight switch. The eyebolt crimped on the end has to go somewhere. Thanks

Adam,

If that case you need to do some detective work on how everything is wire from the autronic-eye pieces hardness, specially from the footswitch since you found it has +12V on the “yellow” wire and if that is indeed coming from the footswitch. ???

The wiring for the autronic-eye is totally different than the one for the standard headlights since the footswitch switches +12V from the headlight switch to each of the lamps for the standard versus the autronic-eye setup which switches ground for the power relay.

HTH
J. Gomez
CLC #23082

55 ledsled

I did some checking with a wire tracker and it is indeed the yellow coming from the foot switch. It does indeed have 12V going to it and goes dead when I turn off the headlight switch, or press the floor switch. Anyone know where that wire gets attached to? Right where it comes out of the wire harness in the photo, is all the length there is and the eye bold was on the end from the factory (no mods). Any help would be great.

J. Gomez

Quote from: 55 ledsled on March 29, 2019, 03:31:49 PM
I did some checking with a wire tracker and it is indeed the yellow coming from the foot switch. It does indeed have 12V going to it and goes dead when I turn off the headlight switch, or press the floor switch. Anyone know where that wire gets attached to? Right where it comes out of the wire harness in the photo, is all the length there is and the eye bold was on the end from the factory (no mods). Any help would be great.

Adam,

If you look at the wiring diagram that I attached to this post -> http://forums.cadillaclasalleclub.org/index.php?topic=149817.0;topicseen this is how the autronic-eye wiring is setup.

You will notice on the autronic-eye diagram the “yellow” wire is connected to the ground at the power relay frame, that is the unit on the left side of your picture it has the “light blue” on one side and the “light green” and “tan” on the other side.
There should be a marking on the power relay case showing “UB” and “LB” under the “light green” and “tan” terminals, these are going to the headlights.

The “light blue” with +12V would be coming from the headlight switch for the power relay “+” and the other would go to the amplifier, which would be the large black box to power them.

The foot switch with ground at the “yellow” wire will switch it to either turn-on (yellow to violet) the power relay to low beams or turn it off (violet to tan) for the high beams.

When the power amplifier is active it will put a ground at the “tan” wire to turn on the power relay to switch the headlight to low beams or removed it for high beams. This only happens when the footswitch is set to connect the "violet" to the "tan"

This is the basic operation of the autronic-eye more or less.

If your unit is not working an easy fix to get the headlight back is to just remove the “light blue” that feed +12V to the amplifier leaving the rest as is. The setup will still place a ground for the power relay from the footswitch “yellow and violet” as long as there is ground coming from the amplifier at the “tan” wire.

Maybe somehow someone did something to that arrangement to get the +12V from the headlight switch to the footswitch.  :o Maybe the autronic-eye was not working so they re-wired it back to bypass it and connected the “light blue” to the footswitch and left things undone.  ???

You would need to trace each of the wires from the autronic-eye hardness to make sure that they are set correctly per the wiring diagram and that those were not butcher or re-arranged.

HTH
J. Gomez
CLC #23082

Glen

This is from the 55 Autronic Eye service manual.  Hope it helps. 
Glen Houlton CLC #727 
CLCMRC benefactor #104

55 ledsled

Wow, thanks a lot guys! I'll let ya know how it works out. Always appreciate the help!

55 ledsled

Everything works! I mounted that yellow wire to ground right on the screw that mounts the relay and they now work! Not sure if the auto switcher works but the headlights turn on. Thanks for your help!

MickeyCaddy

My '55 also has an issue with the Autronic Eye. From what I can see, all the factory-installed Autronic Eye components are in place; when I bought my car it even had little paper tabs on the two knobs on the main amplifier unit, noting their functions.

When I switch the headlights on, they're on low beam for about ten seconds; then they switch to high beam and stay that way. The two floor switches, large and small, have no effect. The fact that they start on low beam, then "click" and switch to high, seems to indicate that the unit is functioning.

After reading this post I checked â€" my yellow wire with grommet is disconnected, the same Adam's (see the attached picture). Unlike Adam's car, the lights do work â€" but mostly only on high beam.

Will reconnecting the yellow wire solve this problem? If not, I've read that disconnecting the blue wire will allow the lights to function as if there's no Autronic Eye; is this correct? If I disconnect the blue wire, should the yellow wire be reconnected?

I'm also wondering why the yellow wire was ever disconnected, both on Adam's car and mine. There must be some common reason for that. I keep finding things that were done to my car before I bought it; they all seem to be related to keeping the car drivable, and with no concern about originality. For example, the glass bowl fuel filter is missing...but I've never had the slightest hint of vapor lock, even after 15 minutes at 85 mph on the freeway, in 110 degrees, with the air conditioner full on.

I'm hoping to get the headlight situation sorted out; when I'm driving after dark people keep flashing their brights at me. Sometimes they drop back and blast me from behind with full high beams. When this happens I just slow down and exit the freeway...but it makes my wife nervous. Me too, a little.

Thanks in advance â€" you guys are the best!
â€"Michael Chanslor
CLC#29849

J. Gomez

#10
Michael,

Quote from: MickeyCaddy on April 19, 2019, 04:53:58 PM
My '55 also has an issue with the Autronic Eye. From what I can see, all the factory-installed Autronic Eye components are in place; when I bought my car it even had little paper tabs on the two knobs on the main amplifier unit, noting their functions.

The two controls on the amplifier “DIM” and “HOLD” have that paper tab across both to lock the control from moving either intentionally or unintentionally  once they were adjusted.

Quote from: MickeyCaddy on April 19, 2019, 04:53:58 PM
When I switch the headlights on, they're on low beam for about ten seconds; then they switch to high beam and stay that way. The two floor switches, large and small, have no effect. The fact that they start on low beam, then "click" and switch to high, seems to indicate that the unit is functioning.

Since you have the ground “yellow” wire removed from the power relay, the unit will function as you noted since the power relay requires the ground to energize it when the headlight switch is “on” to activate the low beams.

After about a 1min or so the vacuum tube inside the amplifier will complete the power on and enable the amplifier circuity.

If there is nothing wrong with the amplifier and/or the phototube back to the amplifier a small relay inside the amplifier will activate placing a ground back to the power relay to keep it energized to hold the low beams (when the footswitch is on the automatic position which is control by the amplifier).

If there is something wrong with either the amplifier and/or phototube the small relay will be “off” thus removing the ground to the power relay, it will be “off” and this will switch to the high beams.

Quote from: MickeyCaddy on April 19, 2019, 04:53:58 PM

Will reconnecting the yellow wire solve this problem? If not, I've read that disconnecting the blue wire will allow the lights to function as if there's no Autronic Eye; is this correct? If I disconnect the blue wire, should the yellow wire be reconnected?

Yes and no;

Yes, connecting the “yellow” wire back will enable the low beam to stay on once you turn the headlight switch on if the foot switch is on the correct position (not on the automatic position) which would have a ground back to the power amplifier.

No, if there is something wrong with the either the amplifier and/or phototube you will not get the unit to switch from low to high automatic.

Quote from: MickeyCaddy on April 19, 2019, 04:53:58 PM

I'm also wondering why the yellow wire was ever disconnected, both on Adam's car and mine. There must be some common reason for that. I keep finding things that were done to my car before I bought it; they all seem to be related to keeping the car drivable, and with no concern about originality. For example, the glass bowl fuel filter is missing...but I've never had the slightest hint of vapor lock, even after 15 minutes at 85 mph on the freeway, in 110 degrees, with the air conditioner full on.

Sorry I do not have an answer for you on this one, maybe the same logic when someone uses a copper penny on the old house screw fuses to keep them from blowing.  :o  :D


Quote from: MickeyCaddy on April 19, 2019, 04:53:58 PM

I'm hoping to get the headlight situation sorted out; when I'm driving after dark people keep flashing their brights at me. Sometimes they drop back and blast me from behind with full high beams. When this happens I just slow down and exit the freeway...but it makes my wife nervous. Me too, a little.


I would guess in your case if you connect the “yellow” wire back to power relay case for ground you will have at least both low and high beams since it seems the amplifier (or the phototube) is not working without the need to disconnect the “light blue” wire that provides +12V to the amplifier from the terminal at the power relay.

Good luck…! 
J. Gomez
CLC #23082

MickeyCaddy

#11
Jose, thank you so much for your expertise, and for taking the time to provide detailed responses to my questions!

Your description of the paper tab on the Autronic Eye adjustment knobs was spot on. I was posting from memory, and I'd confused that paper strip with the little paper pieces I'd found on the headlight aiming screws. They were thin white pieces of paper, and had black text on them similar to "Turn this to adjust headlamp". It was obvious they'd been there since May 10, 1955 (the build date). I have them in a plastic bag.

I remembered that I took tons of pictures when I bought my car in January, 2016. I found one I took of the Autronic Eye "Dim" and "Hold" adjustment knobs, and their paper retainer (see attached pic). It's sort of a thick piece of cardboard; per your description, it keeps the knobs from turning (until it rots away!)

Today I set about reattaching the much-discussed yellow wire from the headlight wiring harness. With its large-ish grommet, I couldn't find anywhere to connect it at first; but I knew that, when built, it was obviously connected to something nearby...and I certainly wasn't going to drill a random hole.

The only chassis (ground) connector that the wire would could reach was one of the bolts holding the driver's-side heater blower motor. It was a perfect match; the wire length was correct, and the grommet was the exact right size (see attached pic).

I bolted it on, and SUCCESS!!! I now have low- and high-beam headlights. This made my day; I'd been going around with this issue since I bought my car. I don't know yet whether the Autronic Eye functions, but the low/high beam foot switch works well...and now I can drive at night without annoying the other folks on the road!

Your "copper penny on the old house screw fuses" analogy is perfect! It explains the dual nature of my '55: it's mostly factory original, as evidenced by the paper tabs on the headlight adjustment screws â€" they started coming off when I first adjusted them, so maybe they were never turned very much. But somewhere in its life, someone did a few "copper penny"-type workarounds, which all seem related to keeping the car on the road without spending much time or money, and without regard to factory originality.

Old cars aren't supposed to speak; but if you listen very closely, after a while you'll find they DO have a story to tell. I still have much to learn, and to me that's one of the best parts of owning a classic Cadillac...even a base model Series 62 sedan!

Thanks again,
Michael Chanslor
CLC# 29849

J. Gomez

Michael,

Glad you were able to get the headlight working at least manually.   8)

Yes the autronic-eye is an interesting piece and if one is not sure how it works is a bit of a challenge to troubleshoot and on the other side it is also very “dangerous” around the high voltage section.

In your case maybe the tech how removed the wire also remove the lucky copper penny and place the blown fuse back.   ;)   ;D

Good luck…!
J. Gomez
CLC #23082

55 cadi

On my 55, I was cleaning up the radiator support and a/c system, then my headlights didn’t go on, I then figured it out, on the upper radiator support there are two small holes, one on each side, a ground wire from light goes up through the hole and screwed in to support with eye hole connector, my lights worked after connecting the two grounds
1955 Cadillac sedan series 62
1966 mustang convertible w/pony PAC, now in Sweden
2005 Cadillac deville

MickeyCaddy

Jose, the headlights are working very well; thanks for your help.

I must admit I’d read about the high voltage in the Autronic Eye, and I was reluctant to get too close. But I was lucky - it was an easy fix, nothing dangerous.

My fingers are crossed; I’m hoping there are no more copper pennies, and all screw-in fuses have been replaced!

;) :o 8)

MickeyCaddy

Adam, that’s really weird! It seems that would be unreliable.

At least you figured it out. I worked on my problem off and on for 3 1/2 years; I was determined to do it myself, but couldn’t.

I saw your picture of the yellow wire and grommet. On a whim, I looked under the hood of my ‘55, and found the same wire and grommet unattached. It was hidden under a hose, and I’d never seen it before. (Doh!)

I posted on the forum, Mr. Gomez came right back with a wealth of knowledge, and the problem was fixed the next day. I could hardly believe it!

That’s the power of a photograph - thanks so much for posting it. And thanks to all forum members...what a great resource!