Fiber optic signal cable going into the passenger door?

GoodOldsGuy

New member
Thread starter
Oct 20, 2020
20
3
Texas
Hey, I was working on my 1979 Custom Cruiser power antenna relay and tracing the wiring to the antenna when I discovered a fiber optic signal cable (like a windshield washer level light) going into the front passenger door through the door jam boot. It originates at a light behind the passenger kick panel and is separate from the courtesy light for the floor on that side. The light bulb in the originating fixture is there and still lights up with the courtesy lights but there is no fixture in the door for it to connect to. Does anyone know of any optional equipment indicator or lights that would have used such a system? It’s a well optioned Custom Cruiser, but it does not have courtesy/warning lights in the door panels like a Regency 98. I can’t imagine that they would install a fiber optic signal light and cable to no where “just in case”. The car was built in Fairfax (Kansas City) KS, and I don’t believe 98’s were built there at all, so I don’t think it was a “oops, put that in the wrong car going down the assembly line” kinda problem. Plus I don’t know if 98’s used fiber optics from the kick panel into the door for any reason either. Side note, my washer reservoir indicator still shows green when full and red when low at 41 years old (I did have to change the bulb though) and my car is not equipped with vigil light fender indicators but I wish it was. Anyway, if anyone knows what the door fiber optic cable was/is for, I’d love to know. Thanks in advance :)
 

Shortfuse

Member
May 15, 2020
60
8
I put in a request to my information service for anything related to this. We will see if they turn up anything. If they send me something I will pass it on. Sometimes though the same parts are used on multiple platforms so it may have been cheaper for them to use one harness on a variety of cars and just plug in what was needed for a particular build. I have seen lots of that over the years of my doing electrical work. Lots of unused plugs and pigtails .
 
  • Like
Reactions: GoodOldsGuy

GoodOldsGuy

New member
Thread starter
Oct 20, 2020
20
3
Texas
Hey, Thanks for seeing what you can find out about it. I agree with you that a lot of multi app wiring harness was/is going on. I’ve just never seen fiber optic cables/fixtures in that situation before, particularly one with an independent light source fixture that has a bulb installed (that still lights up-I found it when I was burned by the bulb while reaching inside the body cavity to follow the antenna harness), illuminating a fiber cable that has been painstakingly strung all by itself to a destination that can only be described as “no where”. I was wondering about multiple applications, since I can’t find a reference to any Oldsmobile that year that utilised any fiber optics in the doors. I have the 1979 Oldsmobile “All models” service manual (published in Oct ‘78-a couple months before my car was built) that describes the washer reservoir and vigil light fiber optics, but no mention of any other use on any Oldsmobile in ‘79. The book is twice the size that the Dallas phone book was back then. Even though it’s rather small compared to the room filling “all models” parts catalog, it’s very comprehensive. The best I can figure out is that the GM Fairfax 1 plant wasn’t building much other than B.O.P. B\C body wagons in 1978/1979. So maybe a Buick Estate, or Pontiac Safari option used them? I don’t even know if Chevrolet B wagons were built there. No C/D body Cadillacs (that would be heavily optioned) were built there either, as far as I can tell. However, Cadillac telescoping steering columns were installed in some Buick/Olds/Pontiac cars at Fairfax 1, so Frankenwagons do/did exist. Sorry for the ramble, I just want to know if I should be scouring old car junk yards for some uniquely cool obscure optional equipment to add to my car :)
 

GoodOldsGuy

New member
Thread starter
Oct 20, 2020
20
3
Texas
Hey, Thanks for seeing what you can find out about it. I agree with you that a lot of multi app wiring harness was/is going on. I’ve just never seen fiber optic cables/fixtures in that situation before, particularly one with an independent light source fixture that has a bulb installed (that still lights up-I found it when I was burned by the bulb while reaching inside the body cavity to follow the antenna harness), illuminating a fiber cable that has been painstakingly strung all by itself to a destination that can only be described as “no where”. I was wondering about multiple applications, since I can’t find a reference to any Oldsmobile that year that utilised any fiber optics in the doors. I have the 1979 Oldsmobile “All models” service manual (published in Oct ‘78-a couple months before my car was built) that describes the washer reservoir and vigil light fiber optics, but no mention of any other use on any Oldsmobile in ‘79. The book is twice the size that the Dallas phone book was back then. Even though it’s rather small compared to the room filling “all models” parts catalog, it’s very comprehensive. The best I can figure out is that the GM Fairfax 1 plant wasn’t building much other than B.O.P. B\C body wagons in 1978/1979. So maybe a Buick Estate, or Pontiac Safari option used them? I don’t even know if Chevrolet B wagons were built there. No C/D body Cadillacs (that would be heavily optioned) were built there either, as far as I can tell. However, Cadillac telescoping steering columns were installed in some Buick/Olds/Pontiac cars at Fairfax 1, so Frankenwagons do/did exist. Sorry for the ramble, I just want to know if I should be scouring old car junk yards for some uniquely cool obscure optional equipment to add to my car :)
Hey, After reading the 1979 Fisher Body service manual (yea-my life is like that lol) I discovered that C bodies (98’s/Fleetwoods) had a lighted door lock cylinder option. The fiber optic line going into the door, on its own inline lamp, located in both left and right kick panels, would lead to the door handle (push button type handle only I presume) and direct light on to the face of the lock cylinder. Vehicles so equipped would also have had door handle switches to activate the courtesy lights and subsequently the lock cylinder light, plus a relay/delay/timer unit that would turn off the courtesy light (including lock cylinder lights) in 30 seconds or when the when the ignition system was turned on-which ever came first. The relay unit was attached to the fuse panel wired into the courtesy light system. I’ve heard people refer to the Custom Cruiser as a C body, but Oldsmobile division and Fisher Body both refer to them as 88 wagons, body type B, series 3BQ, style 35. I don’t know if any C bodies rolled off the old Fairfax assembly plant (where GM made B-25 bombers during the war. I think it’s fitting that B-25 bombers and B Body wagons were built in the same place, even if the gun turret option was not available on the wagons), or if the high end Bui-hogs and Pontiac’s had push button door handles, but it appears that 77, 78, and 79 B Body wagons (at least) came with a C body harness and partially installed options that weren’t even available on a car with an exterior pull up style door handle.
I’m sorry for the long ramble, but I can die in peace now that I’ve solved this mystery (it was a mystery to me at least lol). Peace
 

GoodOldsGuy

New member
Thread starter
Oct 20, 2020
20
3
Texas
Good job. I couldnt for the life of me think what they would use that for but it makes sense to keep you from having to disassemble the whole door to change a bulb.
Me either, that’s why it was killing me. Yea I guess pulling the door panel to change a light bulb would be tougher, but pulling the kick panel off and digging through the all that wiring isn’t a cake walk. The worst part is, since it wasn’t an available option for the B body Oldsmobiles, it wasn’t part of the B body manual. The Fisher Body manual, on the other hand, has all the Cadillac C body stuff included. After reading it, I remembered my Dads 78 Fleetwood having push button door handles, and lighted lock cylinders. I’m a little embarrassed that I didn’t make the connection. That car had all the vigil lights with fiber optics running all over the place. It had a grossly underpowered 425 Cadillac V8, but the completely automatic climate control system, 4 wheel disc brakes, and automatic headlights with self dimming high beams, it was pretty cutting edge in 1978.. and all that stuff was running on relays, capacitors, switches, and diodes.. no computer whatsoever. At least you never had to worry about letting the magic smoke out of a control module. The smoke wasn’t magic, and if you stared at it long enough, you could figure out how they worked. ;)
 

Latest posts