Fiber optic illumination of the dash controls

Dr.Jeff

Dr.Jeff

True Classic
The fiber optic (FO) illumination of the dash controls on the '79 leaves me with one undetermined lead. On my '79 there are 7 strands of FO coming off the light source. One is clipped off near the source; I believe it came this way from the factory? This car was very "unmolested" and original so I doubt it was cut by one of the two prior owners (of which I know the history). And I don't see any place for it to have gone. Anyone know for sure that in '79 there was a cut FO lead from the factory?

The remaining 6 FO cables go to:
Headlight switch (left side of dash), hazard switch, dimmer control, rear window defroster, and dash lights switch (all in the center console). If you were counting that's 5. The 6th one is just dangling loose, and I can't figure out where it might have gone? I should note this is a factory A/C equipped car so the HVAC control panel (vacuum push-buttons) is illuminated by two small incandescent bulbs - not the FO. What else was illuminated by FO on a '79 with A/C?

I went to the '86 parts car to see where its FO leads go, hoping to find my answer. There are only 4 strands coming off that one; headlight switch, two power window switches, and - again - a loose one dangling behind the center console. [The other console switches on the '86 are not illuminated per see (I believe it comes from within, like my spirit for Italian cars).] So once again, where did the last FO cable go to?

Appreciate all knowledge on where all FO lights were mounted on either the '79 or '86 X1/9.
 
My 74 has an extra stub of a fiber hanging out as well. It was like that from the factory. I would not be surprised if the fiber bundle came from a manufacturer that had standard configurations and they just clipped off what they didn't need. The 74 X only used the fiber to illuminate the toggle switches on the center console. My car has four. I never examined the six switch ones with the rear defrost and accessory switch to see if they were illuminated but there is no reason why they couldn't. That is interesting that you have a fiber going all the way to the headlight switch. Mine is not illuminated.

If I ever get around to it, my plan is to replace the fiber with individual LEDs. Then, I would replace the illumination lamps in the instrument panel with LEDs and tie all of them to the center console dimmer pot to control all the illumination together. The two position instrument panel dimmer would not dim LEDs much without a resistor change but the rotary dimmer is set up as a voltage divider so it should work fine with the LEDs. By getting rid of the incandescents, the voltage divider should have enough capacity to run the center console and the instrument panel.
 
dllubin said:
My 74 has an extra stub of a fiber hanging out as well. It was like that from the factory. I would not be surprised if the fiber bundle came from a manufacturer that had standard configurations and they just clipped off what they didn't need. The 74 X only used the fiber to illuminate the toggle switches on the center console. My car has four. I never examined the six switch ones with the rear defrost and accessory switch to see if they were illuminated but there is no reason why they couldn't. That is interesting that you have a fiber going all the way to the headlight switch. Mine is not illuminated.

If I ever get around to it, my plan is to replace the fiber with individual LEDs. Then, I would replace the illumination lamps in the instrument panel with LEDs and tie all of them to the center console dimmer pot to control all the illumination together. The two position instrument panel dimmer would not dim LEDs much without a resistor change but the rotary dimmer is set up as a voltage divider so it should work fine with the LEDs. By getting rid of the incandescents, the voltage divider should have enough capacity to run the center console and the instrument panel.
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The headlight switches on both the '79 and '86 have a fiber optic line going to them. Being located on the left side of the dash it is a long reach.

This dash is undergoing a number of custom changes. I removed the console switch for the dash lights and the dimmer is the later "electronic" version, so it will control all of the dash illumination. The instruments are replaced with round ones like on a 124 Spider. They have the warning lights built into the dials, plus illumination lights. All those bulbs will be replaced with LED's. The console switches are getting a revamp as well; retaining only a couple of them but relocating everything. The existing fiber optics will still work for them so I might just change that bulb with a LED rather than install individual LED's in each one. The HVAC controls have undergone customization also, now there's only one bulb for all of it. I can use one of the spare fiber optic lines for that. So all in all it would be much easier to just swap a single LED 'T10' bulb to feed the fiber optics than adapt everything for individual LED's.

There isn't any info about the fiber optics in the factory service manual (at least not that I could find). I imagine the "cut" fiber optic cable was done at the factory. As you described on yours, it is cut a couple inches from the light source. But I cannot figure out what the extra fiber optic line if for - on both cars. The end has a plastic holder like the others. It is located near the center console switches, but they are all accounted for. The cigarette lighter and ashtray don't have a place for a fiber end. I can't think of what else was there? Did they just leave an extra one for some option that might have used it? Strange that both cars have an extra, especially how different they are otherwise (see my prior post).
 
My car 79 had a fan switch in the normally blank spot. It was wired to the control the carb fan but the was removed. I wired it to my second radiator fan so I could turn it on manually ahead of the thermo switch. It was nice to have the extra optical lead to use for that switch. Maybe that is y it was included in the factory setup. Not sure if there are other uses for that extra switch spot?
 
Bobkat said:
My car 79 had a fan switch in the normally blank spot. It was wired to the control the carb fan but the was removed. I wired it to my second radiator fan so I could turn it on manually ahead of the thermo switch. It was nice to have the extra optical lead to use for that switch. Maybe that is y it was included in the factory setup. Not sure if there are other uses for that extra switch spot?
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Good idea with the carb fan, although, what happens if it's left to owner-control, and you forget....exploding carbs?
 
Bobkat said:
My car 79 had a fan switch in the normally blank spot. It was wired to the control the carb fan but the was removed. I wired it to my second radiator fan so I could turn it on manually ahead of the thermo switch. It was nice to have the extra optical lead to use for that switch. Maybe that is y it was included in the factory setup. Not sure if there are other uses for that extra switch spot?
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The last switch hole on my '79 has a blanking cover on it, so no extra switch. But what you said makes good sense, the dangling optic lead may just be for any cars that used that extra switch location. However I keep wondering if it actually was connected to something that I've forgotten about?

Also, the fact my '86 parts car also has one hanging like that makes me wonder, because that has a completely different setup for the fiber optics. But that car has been messed with a lot, so no telling how stock it is.
 
bbrown said:
Cure the problem ...
Replace Fiber optics with LED's
Note: The link above is for the late model Fiber Optics. Earlier versions merely require the appropriate housing for the ends.
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Thanks Bob, I will be doing LED conversions. However my main concern at the moment is where the other optic lead goes to? There's one that I can't figure out where it went. I'm trying to remember if there was something else that got illuminated by this? This is for a '79, which is different from the earlier and later cars.
 
These days it is easy to find LEDs packaged with voltage dropping resistors that fit into the switches so I would dump the fiber entirely and just put an LED in each switch.

On my car, I discovered why one of my switches (instrument panel dimmer) had been much dimmer than the rest since 1974. Last time I had the console out, I discovered that they had pinched and damaged the fiber pretty bad at the factory. I removed the damaged section and butt coupled the remaining pieces. Unfortunately, these fiber bundles lose lots of light when butt coupled, even when polished and with index matching, due to the packing factor losses. Bundles have a tighter bend radius but for the way the center console is routed, Fiat could have used solid core fiber and the stock results would have been much better. The 1mm core plastic fiber, like they use in Toslink audio applications would be a good replacement for the bundles if you plan to stick with fiber.
 
I don't get the issue with the fiber? I think it's pretty cool myself. I'm not one for keeping things stock but for some reason I like to keep the appearance of stock. I guess there was something that attracted me to the car, maybe it wasn't all outside. Anyhow, My thought was to change the single bulb to an LED.
 
ricar said:
I don't get the issue with the fiber? I think it's pretty cool myself. I'm not one for keeping things stock but for some reason I like to keep the appearance of stock. I guess there was something that attracted me to the car, maybe it wasn't all outside. Anyhow, My thought was to change the single bulb to an LED.
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If your fibers are all in good shape, changing the bulb to an LED would be the most straightforward approach if you can find an LED with significant light output coming out the top of the bulb where the photons can find the fibers. Someone posted a while back that the LED bulb they chose had most the light coming out in other directions leaving the fibers a bit dim. One way around that would be to take an LED and butt the ferrule holding all the fibers up against the direction where most of the light is coming out. That metal can fixture that the ferrule plugs in to was designed for the radiation pattern of an incandescent is not optimal for LEDs. I've run into a similar issue when replacing front panel incandescents with LEDs on various electronic equipment. Sometimes the light output uniformity gets compromised because the optics were designed for an incandescent light source.
 
As much as I enjoy the discussion :), just to keep things a little bit on track....

The question here is NOT about fiber optic vs LED or any other options. The question here is WHERE did all of the fiber optic lines connect on a 1979 X1/9? :oops:

I've identified 5 of the 6 optic branches (not counting the 7th one that was apparently cut at the factory). Those five go to the headlight, hazzard, dimmer, rear defrost, and dash light switches. The sixth one is in the same region as those console switches. It has the same plastic "connector" piece on the end as the others. But I can't figure out where it goes.

One suggestion is that it may be there (redundantly) if another switch was included on the center switch panel (typically there is a blank spot on that panel). This may be the case but I'm hoping to confirm things. Have any other '79 owners found the same thing...a unused optic lead sitting behind the center console? Or better yet, anyone find a place that it actually goes? ;)
 
tvmaster said:
Good idea with the carb fan, although, what happens if it's left to owner-control, and you forget....exploding carbs?
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Eventually gasoline in the carb will boil and the car might be difficult to start until cooled down. Explode, probably not.
I have a fan for cooling the injectors triggered by ECU but the fan shuts off when ignition is off. Never had a problem with that.
 
Bjorn Nilson said:
Eventually gasoline in the carb will boil and the car might be difficult to start until cooled down. Explode, probably not.
I have a fan for cooling the injectors triggered by ECU but the fan shuts off when ignition is off. Never had a problem with that.
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My old, original 1300 carb arrangement often runs the carb fan, on and off, for about thirty minutes. Can’t imagine how much hit the battery takes...
 
Back to the LEDs. I did the search for the extra Fiber line and as it was so short and could only be somewhere around the swiches I just assumed it was for the blank switch. Only one is long enough to reach the headlight switch. Not long enough to reach the cigarette light position or the ashtray ( not sure as i do not have and ashtray)

I would use these little T5/74 bulbs if I was to do the LED swap. Most come with a socket and that could be glued to the back of the switch. Would make a clean install without resistors inline.

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I did fool around with the color of the the led in the fiber optics main main bulb. After I did all the wiring updates and changed all the Instrument cluster bulbs to LEDs the dominant color was white and just seemed proper. I ended up modifying one of those 9W eagle eye LEDs ( same ones i used for little DTRLs) that slides right into the light distribution thingy. They are super bright and seem to do a much better job of lighting through the old fibers. A few of my fibers were kinked. So I was going to replace them with LEDs. I ended up splicing out the kinks and smoothing and gluing the ends back together with shrink wrap.

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Thanks @Bobkat. So your '79 also had an extra optic line just hanging out behind the center console?

I also thought maybe it might have been for the cigarette lighter, but all of the ones I have use a seperate light bulb with its own wire...if they have any light at all. And none of my ashtrays have any provision for a light of any type. So I'm inclined to agree with your assumption that it was left there in the event a option of some sort used the extra switch location. I'm not certain but I think there were some markets that included a rear "fog" light with a switch? I'm sure the spare switch hole was used for something at some point on some cars. But it is kind of funny that they clipped off the 7th (unused) optic line but left this one. And being a complete line it would spread light back there behind the console (although these are so dim you'd never see it).

Thanks for the feedback on your LED's as well. ;)
 
Dr. Jeff, the 6th & 7th one was to the motorized window switches. In EU, there was a rear red fog light.
Some switches had lamps built-in, some not. The window switches did not AFAIK.
 
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