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Have already searched some of the old threads on fiber optic troubleshooting. I have some lights but not all lights. Can't quite figure out how to get the other fiber optic lights to light up on the front and rear display panels?
Wondering if someone has time to give me phone call and help walk me through additional things to check..... Will look for a PM and then provide a cell phone number to you. Patience required. I am not a mechanic or an electrician. I am learning. I have the center console loose and I have access to both the front and rear fiber optic cables, lenses, display panels.
With Headlights on and high beams on and ignition key on accessory on the steering column, I have the following lights on the front fiber optic display: RIGHT LAMPS Red (on) Blue (off) White (on). I did put new repro plastic in - thought they would light up brighter than the old ones. The front fiber optic cables, harness, and brass connectors are original to this 1969. LEFT LAMPS White (off) Blue (on but barely visible) Red (on).
Rear Fiber Optic display LEFT TAIL LAMP (off) LICENSE PLATE (on) RIGHT TAIL LAMP (off). I did put a new repro plastic lens in the rear display too for the same reason - thought they would be brighter than the originals and the LEFT TAIL LAMP portion of the plastic lens was broken and missing. The rear fiber optic cables, harness, and brass connectors are original to this 1969.
I can't put the front center console back in the car and secure everything until I get all the fiber optic lights working so I've hit a bit of a wall. The 5-Gauge cluster and the gauge bezel and radio are out of the car at the moment while I try to figure out the fiber optics and get them all working. The fiber optic displays were not all working when I took the center console out and changed the lenses.
I could use some help if you have the time to talk me through additional things to check. Thank you in advance.
We are making progress. Thank you so much for reaching out. As of 7:52 pm, I now have all three forward RIGHT LAMP and LEFT LAMP fiber optics lighted and working. High beams are a little dull so I may spend some more time trying to clean the ends of the fiber optic cables.
On the rear display behind the shifter plate, I have the LICENSE PLATE light, changed the bulb and it is a little bit brighter. I have the two fiber optic boots and it looks like the red tip is located in the rubber boots inside the tail light housing but so far no RIGHT TAIL LAMP or LEFT TAIL LAMP fiber optic light. Looks like the fiber optic cables are intact from the tail light housing to the wire bundle feeding the light. Will pick it up again in the AM. I'll try your flashlight trick in the morning and see if the LEFT and RIGHT display inside the cabin area.
Total Score : I've now got 7 out of 9 total fiber optic display lights working on this 1969.
3 Pointers from my experience:
- On the tail lights, make sure the receiving lens on each housing is intact and clean. On my '69, a prior owner had not masked off the housings when the car was repainted, so they both were seriously over-sprayed with blue paint. Cleaned them off and that helped significantly for the rears.
- At the console, check that you have light coming in to the bare ends of the fibers. That will be the best light output you can hope for. The plastic lenses only disperse the light, and they need have the cable angled and secured properly in their receiver tubes. I used a proper size shrink tube on each to thicken up the OD to match the ID of the lens tubes, exposing about 1/2" of the actual FO cable at the end. Then I shoved it tightly into each tube and then a dabbed super glue around the outside seam to hold it tight.
- Lastly, it's a good idea to have a good clean end of each FO cable before connecting into the lenses. I was given the tip to take a VERY sharp razor, and slice the very end of each cable to give a nice smooth perpendicular cut surface. This improves the light output as well.
Keep in mind, even when they all are working at 100%, you're not going to get a very high level of brightness out of the lenses. They're only meant as bulb monitors.
Some have gone another direction and abandoned the FOs, and just wired LEDs in the lenses. I would consider that a last resort.
Good Luck!
Kudos to you for giving your all to try to restore this unique (but very cool) feature of our early C3s.
Just a couple suggestions. Remove taillamp lenses to make sure fiber optic lens in lamps have not been painted over. Also, I replaced my headlamps with halogen bubs and noticed headlamp indicators were not as bright. Finally figured out factory T-3 bulbs have a glass bulb on the back center of the sealed beam right where the fiber optic reads. Halogen replacements have a blob of silicone there that I believe mutes the light signal somewhat. I had one fiber optic cable that had been cut into. I repaired by cutting both ends perfectly flat with a razor, then butting them together inside a piece of vacuum tubing. Wasn't noticeable after wrapping back to the harness and it worked perfectly. Chip.
Interestingly, the headlamps have a glass "appendage" on the back of each bulb...the place where the lamp is evacuated and/or filled with inert gas. The F/O cable is imbedded in the center of the electrical connector for the lamp; and there SHOULD BE a piece black plastic tubing between the connector and the rear of each headlamp, over that appendage. That is how the light enters the F/O cable. The black tubing prevents outside light from entering the connector. Most of the time, those little pieces of tubing are missing, and light transfer into the F/O cable is reduced. You can use some stiff 1/2" black plastic tubing to substitute for the stock pieces. Measure the space between the connector and headlamp (when they are connected) to find the length of tubing to cut. I think 1/2" light-duty water irrigation tubing (found in hardware stores) will do the trick.
In general, you need to clean up, polish, etc the bulb-to-F/O cable junctions in your system. They can be dirty, painted over, damaged, etc. so that light from the bulbs does not feed directly into the cables. That's what needs to be corrected.
I am taking notes and implementing the ideas and suggestions coming in. Thank you for sharing your expertise.
Today, I was able to pull the 3-pin and 2-pin connectors from the LH and RH low beam and high beam lights, cleaned up the male end of the FO light in each of pin connectors and then also cleaned the small glass standoff on the low beam and the round center portion of the high beam. There was no short section of rubber tubing between the male FO and the back of the low and high beam.
Very happy to report that all three RIGHT LAMP and all three LEFT LAMP FO's are not only working but after a good cleaning behind the headlights and the running lights they are all nice and bright and very easy to see with the garage overhead lights off. Success!
Will continue to work on the LEFT TAIL LAMP and RIGHT TAIL LAMP - nothing yet, not even a dim light at the lens. LICENSE PLATE is working and faint at the display inside the car, even after cleaning and after putting a new bulb in the socket, but I'll continue to work on that and the rear FO's. The FO's are there, red tip of each of the FO ends are in place in the tail light housing. Both LH and RH FO's look intact under the car, no broken FO's, splits, pinched or damage that I can see so far.
I positioned a very bright LED headlamp and then positioned my MAG flashlight right at the red tip of the FO inside the housing for the tail lights with the tail light lens cover off, pulled the switch out for the running lights and then the low beam headlights.....nothing. Not even a faint light on the LEFT TAIL LIGHT and RIGHT TAIL LIGHT display inside the car.
Must have two broken cables somewhere in the line for the tail light FO's?
Maybe...but not necessarily-- If the car has been repainted, it is very possible that overspray could have blocked any light getting to the F/O end. You will need to remove the tail light lens and check the condition of the red plastic 'cover' over the cable ends.
Maybe...but not necessarily-- If the car has been repainted, it is very possible that overspray could have blocked any light getting to the F/O end. You will need to remove the tail light lens and check the condition of the red plastic 'cover' over the cable ends.
Good Morning 7T1Vette,
Car has been repainted once. Yesterday, I pulled the RH rubber boot out of the tail light housing which contained the red plastic lens. I removed the red hard plastic lens, it was pretty clean and in good shape but I did take it out of the rubber boot and polished it up good. Next I took a very sharp X-Acto knife and cut off about 1/32" off the end of the FO cable, pushed the FO cable up just tiny bit inside of the brass housing, put the brass housing back into the red hard plastic lens and both of those back into the rubber ferrule / boot and pushed the boot back into place in about the 7:00 o'clock position in the RH rear tail light housing. Connected the battery disconnect, pulled the LIGHT switch out the first running light position (nothing), pulled the LIGHT switch to the full out position and left and right lamp displays in the front console came on but nothing in the RIGHT REAR LAMP display. Also took my high-powered LED headlamp and positioned it right in front of the red plastic FO lens in the right tail light and checked the display inside the car with the garage lights off and (nothing). Checked to make sure the other end of the FO had not come loose or fallen out of the center console FO display behind the shifter and it was intact and snug in the plastic lens under the shifter plate.
Will do the same (remove, clean, polish, trim FO cable, reinstall) process on the LH tail light this morning and see what happens. It too is free of paint overspray just from a visual look with the tail light cover off. Red plastic lens looks to be intact, did not see a broken FO cable on my first glance under the car yesterday.
Thanks everyone for continued ideas and suggestions for FO troubleshooting. I am certainly learning more about FO functions than I knew a few days ago.
Kevin
Last edited by KS69Coupe; Oct 9, 2020 at 10:13 AM.
There were Sylvania Super Bright 1157 LED bulbs in the tail lights on Monday of this week when I started trouble shooting. I went ahead and put the regular standard 1157 bulbs back in the rear tail lights thinking perhaps the LED lights mess with the FO display. LEFT TAIL LAMP and RIGHT TAIL LAMP FO displays inside the car do not work with either super bright LED bulbs or the regular 1157 bulbs. So, I ruled out LED bulbs as a variable.
Unless you have already been inside the trans console, it is possible that the F/O cable ends have dislodged from the display lens piece. Or they were intentionally removed or cut. Just need to take the 4 screws out of the shift plate and do the deed to open it up to find out what's 'cookin' .
First, big THANK YOU for all the help, ideas, suggestions, and things to look for while troubleshooting the fiber optic cables and indicator light displays on the center console of this 1969.
Second, troubleshooting the LEFT TAIL LAMP and RIGHT TAIL LAMP was a challenge. At the advice of twinpack (Peter) this morning, I started to remove the non-stick wire wrap containing the wiring for the tail lights and the fiber optics behind the left wheel well under the car. Then came the "ah ha" moment.
About 11-years ago my son had Flowmaster mufflers put on this car to beef up the sound of the car. No issues with that since we bought the car as a father / son project. It looks like the people who did the muffler work damaged the original wire bundle, did not know how to repair the fiber optic cables, and then just re-wrapped the wires and left the loose ends of the right and left tail light FO cables. LICENSE PLATE LAMP FO cable was spared.
FO splice kit is on the way. Thanks again to everyone who helped me get this fixed. So much experience, talent, and Corvette knowledge here on Corvette Forum.
Unfortunate circumstance, but glad you've finally found the 'culprit'. Now you know what to do...and when done with the 'fix', F/O's should work as intended!
Fiber Optics - 69
