FIBER OPTIC Turn signals indicators

[Troyaero]

My 75 Eldorado has the fiber optic tubes running from the light pods to small indicators on the left and right fenders.  None of them work and rightfully so since they have all been broken or disconnected,  I really suspect this car might have saw a round or two in a demolition derby since I have the feeling over the years it may have been wacked from all four corners...maybe.  Well I know this form of turn signal indicator was used as an option on other GM products too I am told.

Since none of it works I was looking for some leads into help for restoring the system.  I do have the convertible and I have read that the HT version had an indicator in the back somewhere and I guess you viewed it through the rear view mirror ??  I guess the convertible did not have that ?

Tim

[TJ Hopland]

The hard tops it was on the roof near the back window.   Convert it was a little pod on the top of the seat back.

If you know the cables have been cut or damaged you have to deal with that first.   If the cables are connected then you need to look at the lamp end.   The tail lights and turn signals have a 'collector' lens in the reflector that the optic connects to.  Sometimes these can just be very dirty and just need to be cleaned.    The headlights the fiber goes into the center of the electrical plug.   Vintage headlights had the sealing nipple there with a foam gasket to help direct the light to the fiber.   More recent lamps just have a plastic seal there that does not emit as much light as the original ones did. 

I have not tried it but have heard that you can splice the lines.   You just need a sharp cable cutter, the kind where the blades are a hook shape vs straight.  You just get a clean cut, butt the ends together, and shrink tube to keep em clean and together. 

[savemy67]

Hello Tim,

I once owned a 1980 Buick Electra Park Avenue 4 door sedan.  The car had the fiber optic indicators.  They were located where the rear window top garnish molding and headliner met.  The indicators were at the center of the garnish molding, and they were observed via the rear-view mirror.

Depending on what is broken on your car, you may be able to find an intact cable assembly at a salvage yard for a few dollars, and use it on your Cadillac.  Splicing a broken cable could be a hit or miss proposition.

Christopher Winter

[Troyaero]

Thanks for the input guys.  Well my fiber optic system is mainly trash due to the poor maintenance over the years,  Guess the owner didn't care about a functional turn  system indicator. 

I retired from a career in telecommunications and was trained in the use of using and making fiber optic cables.  Problem is they each have their own method of preparing the cable ends.  There are special tooling for all of them made to cut and polish the ends of the fiber,  Don't have the tools and you are down the drain,  When you cut the cable it shatter's the inside of the glass fiber.  Maybe the newer stuff is different.

Guess if I ever want to see it work again I'll have to go look up some old "friends".

I guess the convertible had no rear indicator assembly ?   BUT, there are cables run to the back lights.  Hmmmmmmm.....

[TJ Hopland]

As I said in the first line of my reply the converts had a little pod on the top of the seat back.    You can see it in this photo.   Its all plastic and I presume brittle the older they get the easier they would be to break.




The fiber optics in these is not very precise.  What I have been told is sometimes a splice turns out not to transmit much light you try again and it usually works.    I think I remember being told that you can test em after you make the cut with a small flashlight.  If it comes out half dark its likely what you said where you crushed some of the stands. 

[76eldo]

If you keep looking on ebay you will find the lines when guys part cars out.

Part of the problem is that they sights on the fenders get painted over, and on the front headlights, they get replaced and the little pick up spot either isn't there or doesn't get reconnected.  If the front bumper was ever off of the car chances are the fiber lines are no longer connected to the parking lamps.  They have a clear tube in the back of the parking lamp that commonly breaks off when guys try to pull the lines out at body shops.

Brian