C3 Fiber Optics
 

Thanks to those who gave advice concerning parking brake indicator light. Long story short the parking brake switch tested ok with multimeter and it ended up being a blown bulb in the RPM display. Changing that bulb requires you to have more flexibility then I thought I had since it is replaced under the dash at the top of the RPM display (quite a stretch). Next question, I recently replaced the holder for the fiber optics display of the tail lights/license plate light. One of the tail light display wires is very weak. I pulled off the end of the connector and cut off the end of the fiber optics. The brightness got a little better, but did not improve greatly. Is there a trick to making the tip emit more light?

use a "brand new" razor blade to make the cut "squarely"

thats the best you can do at home.

To fix that bulb I took off the lower bezel with the headlight vac switch, lowered the steering column (two bolts) and took the screws out of the speedo/tach pad. I then went between it and the top dash pad to touch that bulb. It is still tricky but can be done.

I did this job last week. Be sure to check the lights before you button it back up. On my '76 the headlight harness likes to shift and then my interior lights won't work.

Good luck

Hi ESC,
I also found that cleaning the various lenses (the part you see when in the drivers seat) helps the visibility too. The lens is grooved and holds any little bit of dirt that happens it's way.
It's easy to clean (tooth brush) so worth the try if you haven't done it yet.
Regards,
Alan

Check the BULB end, mine had overspray from the last paint job. I think I just scraped it with a razor, it might be nice to polish the "lense" with a dremel and compound, but I didn't. Make sure the f/o isn't broken along the way.

Fiber Optics
 

I have a single fiber optic line from the tail light that is not functioning at all. Ecklers offers a repair kit, but it gives no details of the length of cable. Does anyone have any experience with this product or has anyone run a single strand fiber optic line from the rear tail light up to the counsel (near gear shifter). Is running this line difficult.

I don't have a clue how this fiber optic system works. I am going to install a heavier gauge harness for stronger lights, and don't know how this will effect the fiber optics,etc. I think I will use the alternator as the power source?

Fiber optic cable is kinda like simply multipile strands of clear "Fishing Line"
you shine a flashlight at 1 end, you should be able to see light at the other end.
if the ends are clean /crisp, freshly cut with a blade. they will work unless they are cut.
the splice kit is just that, incase an accident, or bubba cut your optic cable,
they are made to splice the cut ends together, you will loose a percentage of light transmission with a splice, light loss depends on quality of optic cable splice.

I've replaced individual strands of fiber optic cables, buying the fiber optics bundles in bulk. I believe they were made by Dupont (been many years since I did this), info on the jacket if you unbundle them. I bought mine from Edmund Scientific, exactly what GM used. I don't think they sell them anymore but some other vendor may.

Other options are to buy a replacement fiber optics harness, seperate from the wiring harness. Many vendors offer them. If your wiring is old you may want to consider replacing the whole harness with fiber optics.

I've tried splicing bundles, didn't work very well, too much light loss.

Dim tail light indicators is likely due to the little red plastic insert (at the tail light end of the FO system) becoming dirty and/or cloudy from age. Try to remove it and clean/polish it with toothpaste and a Q-tip. Anything you can do to clear/clean that little red 'lens' will improve indicator brightness. Also, verify that the bulb is well aimed at that lens.

Cutting the end of the FO cable to get more brightness is 'iffy'. It has to be polished, as well, or you likely will get little improvement. Cleaning the existing end probably has more potential than cutting it.