redbarchetta74

Thanks to the forum, I was able to fix all but a single fiber optic run (grrr!) back to the consoles with pretty good success. However, I have one cable (passenger parking/turn signal) that simply isn't passing light and I have no idea why. I have trimmed/squared the end with a sharp razor blade, but still cannot seem to get any light back to the console. I also pulled the console and everything seemed to be in order with the cable entering the lens. The cable has a pretty good turn/kink as it runs into the lens, but they all look that way.

How does one go about resolving this issue? Run a single new cable to the front end? If so, any advice on where to pass it through the firewall, or just run parallel to the original harness? How long of a run should I look for? I noticed that there are some used fiber optics on EB for '89 - '94 Cadillacs, but they are generally 9 or 10ft in length. Is that long enough? I also noticed that Amazon has some cut-to-length 14 strand (5mm total diameter) cable, but I have no idea if that would work right or not. I'm sure I could fabricate ends to fit properly into the lenses, but I wanted to check here first to see what everyone else has done (short of replacing the entire harness). It drives me nuts that all but a single FO isn't working.

Alan 71

Hi rb,
???
Have you installed the f/o connector in the parking light housing but used a bright (100w) bulb on an extension cord in the housing to see if you see anything in the interior?
Have you shown a bright light at the underside of the interior lens to ensure the lens isn't block?
Adding an addition cable by wrapping in the existing harness is possible if it comes to that.
Are you aware that the f/o harness separates from the lighting harness on the compartment side of the harness?
Regards,
Alan

redbarchetta74

Thanks Alan. Your posts on this subject were particularly helpful to get me this far. Some responses to your questions:

No, but I did use a large mag-lite to test each FO connector before placing back in the housing. All checked out except the passenger-front one.

I pulled the console today and managed to shine some light on the underside. All good on all lenses. By the way, is there a better way to get access to the front FO lens assembly without pulling the entire console?

I may end up having to do that, but I'm trying to determine if it would be best to source a used cable (EB) or try to fabricate something from some new fiber optic cable. I was not exactly sure where the FO separates from the lighting harness, so that is helpful to know.

TimAT

Look about 10 inches below the wiring harness firewall connector, The fiber optics break out and go into the cabin in that area. If you can find the break, the vendors carry single strand repair kits.

theandies

yes, the best way to test it is to remove the FO cable from the housing and shine a flashlight into the cable. If you don't see any light on the interior indicator you cable for that lamp is broken somewhere in the harness.
You can find FO cable the problem I see in replacing it is a PITA to run it from the lamp housing all the way into the interior. To me that's a lot of work and it can get pricey.
I do like the FO system as it's told me my brake lights weren't working and just recently I had a high beam go out. Knew immediately which one.

redbarchetta74

Thanks - I can get a used FO cable from a caddy via EB right now, but I have no idea if it would be long enough (9 footer). I've cleaned-up the end toward the front of the car...but I can barely get any light through the cable. What are the odds that the problem is on the console end? The lens is clear and the FO seems to be firmly seated into the console end.

VERYSOON

I think the fiber optics system is cool. All work on my 69. Had to repair only the passenger side turn indicator. I did it the cheap way by ordering a few feet of cable and a coupler from a fiber optic place. My experience is every splice diminishes the light at the console. soooo.... if you want to do it totally right you can get a correct single optic fiber cable from lectric limited, I believe a vendor here. Expensive but less than a complete fo harness. otherwise I was able to get a visible indicator with my two splices (cable crushed at headlight) for $6.70!

VERYSOON

theandies

You are correct. I did a paper in collage (electronics engineer) on the degradation of signals through various types of splices of FO cables. Now this was investigating data loss but if you loose light you loose data. A straight, Un-spliced cable is the best.

CraigH

I tracked down two breaks in one of my rear fiber runs in my 71. Was easier to just run a new length of fiber.

redbarchetta74

I'm thinking of doing the same thing -- where did you purchase a new length of fiber and how did you terminate it on both ends?