2 cluster questions

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JGSR66

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1985 c20 I know this is the VSS and goes under dash behind wheel but not sure how to install, does it just hang there?
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The man I bought this from started restoring then passed on before he left this earth he converted cluster (all of cab) to LEDs but I m not sure what this is for or where the end of wire goes
Top left


It’s a dog eat dog world & Im wearing milkbone underwear
 

yevgenievich

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The wire is a fiber that passes light to the ash tray area. On the optical speed sensor, the black part inserts near the Speedo drive and has a single screw holding in place. Other end mounts separately and has wiring connect for cruise control
 

JGSR66

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Ok I found the insert for OSS thank you. Now does that black fiber need to be connected to something or just lay behind dash?
 

bucket

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Ok I found the insert for OSS thank you. Now does that black fiber need to be connected to something or just lay behind dash?

It sticks into the upper left corner of the ash tray housing.
 

JGSR66

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What is it for?
 

RustyPile

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Fiber optic is a material that will transport light, much like a pipe transports water.. The dash light shines in the end of that fiber optic and shines out the other end.. If you place the other end of the fiber optic in the ash tray housing like bucket said, the light coming out the end of the fiber optic will illuminate the ash tray... These old square bodies of ours are full of little "trinkets" like that...
 

JGSR66

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But I have a light there already in a socket
 

chengny

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But I have a light there already in a socket



Inside the ashtray? Man, I have to tell you.

I have historically pretty much refused to install anything but NOS parts in these trucks. But the supply of new old stock has pretty much been exhausted over the years and what is left is insanely expensive. Consequently, a business decision was made to relax the NOS rule. But only to the extent that if NOS was not practicable (due to price/availability) to still only use OEM parts. That forced me to just about live in junkyards since I got my first Square Body - a 1986 Sierra Classic in 1988 (Jeez, that was 30 years ago!)

Anyway, over those 30 years I have climbed through literally hundreds of GMC/Chevy pickups and I have seen a lot of interior variants. But I do not believe I ever saw an illuminated ashtray - other than by the fiber optic cable method.

There is a courtesy light that came factory installed under the dash - between the ashtray and glove box openings. Maybe a previous owner thought that a light would be more useful mounted in the ashtray - and relocated it there. It wouldn't be a hard thing to do, there is plenty of slack in the wiring harness to allow it to be shifted over a few inches. I haven't smoked in 20+ years so the a-tray is usually just a piggy bank. That sounds like a good idea - I think I will do it too.

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74 Shortbed

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Both of my Burbs has that light there, but they don't have that screw there that's circled???.
 

smoothandlow84

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My 84 had lighted ash tray....but I removed it since the ash tray compartment holds my air gauges. The gauges themselves are illuminated. I ended up wiring in leds to the power wire for under dash (center) illumination instead. Ithought everyone had a lighted ashtray...huh.
 

JGSR66

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I did mention that the elderly gentleman who owned before me died in middle of restoring not sure what all is complete Got a couple wires under dash & hood that are hot but go no where

Anyway back to point I found where optic cable goes & im guessing that since it’s LED then the extra was added by the elderly gentleman who passed away restoring it.
I’m going to add that phrase often, reminds me of Christine
 

echo7bravo

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I got my first Square Body - a 1986 Sierra Classic in 1988 (Jeez, that was 30 years ago!)

Jerry telling his age on us.

GM had use fiber-optic wiring to spread the instrument lighting to the shift indicator on the C10 back prior to 73-87's. And with NOS fiber-optic it worked really well. And now are the days of LED and resisters to control illumination brightness.

I can appreciate those who keep things original and working the way they were designed. However, I totally understand utilizing more modern technology to accomplish the job.
 

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