Topic: '76 cb550 tail light issue. Help Please!!!

[msalgado44]

Hello all! I own a 1976 CB 550, and am having issues with the tail light. The brake light activates, and the tailight works in the Acc position on the keyswitch, but I cannot get it to activate during normal running. The harness and light is stock, I beleive everything is correctly connected (According to my Honda Wiring diagram). Luckily here in NC this bike is too old for a safety inspection, so I wont fail, but I would like to ride at night and not get a ticket, since you cant read the license plate! Any body have some advice? Thanks!

[KingCustomCycles.com]

Got the same problem on my 69 CB750.  I was going to spend a few minutes tracing down the open wire then if that failed just run a new brown wire from another key switched positive source and be done with it.

[msalgado44]

Could that taillight be spliced into the headlight circuit?

[Nortstudio]

Just a thought:  have you checked to make sure the ground wire has a solid connection?  When I replaced my tail light on my '76 550k I had all sorts of weirdness (on when power, off when I hit the brakes). Turned out the ground wire wasn't making good contact.

Good luck

Scott

[KingCustomCycles.com]

Yes, any switched positive will correct the problem.

[msalgado44]

All grounds are solid I beleive. May try splicing into headlight... Three wires lead to the rear ligh assembly any ideas which operates the running light? I know green is ground, ithink there is also a brown and striped wire? Is Brown the running light?

[Nortstudio]

Just try it both ways - you'll know in seconds which is correct. I can't remember and I'm not in front of my bike.

[msalgado44]

We have lift off! Perfect solution of splicing into the headlight circuit. On my '76 there just happens to be a spare brown wire in the headlight bucket, some sort of euro spec option for parking I think. Cut off the end, tied onto blue headlight wire since I always keep hi beam on and Voila! We have a fully functioning tail light. Thanks for the suggestions all!

[lone*X]

Sounds like you need a wiring diagram and some manuals.  Their free on this site.  Wiring diagrams will let you trace the tail light wiring and possible find the gremlin.  Better to fix it correctly than be someone else's PO.

http://www.sohc4.net/?page_id=207

[msalgado44]

Since i now have power to the light i am thinking the issue was my keyswitch, i plan on replacing it, however I have to have it inspected for roadworthiness tomorrow and was in a bind to get it don asap. As you can read above i DO have a digram and manual which is how I made this repair and know I need a new keyswitch. As to being someone's next PO, i got this project as a gift from my
Dad, and plan on keeping it for a long time (read as Forever). Thanks for the advice.

[lone*X]

Gotcha.  Temporary fix is OK.  Keeping it in the family is a good thing too.  Still have my 75k1 which I purchased new so I know how that works.  My only concern was that we read so often about the suprises that new owners find in the wiring harness from "fixes" by the previous owner.  It's always best to get it right.   

[stidds]

Glad you sorted you problem, I was going to add though (and you have already though of it) that I had exactly the same problem with my 550K and the problem was the keyswitch, I replaced it and everything worked well.

[Spanner 1]

The actual fix is that the taillight fuse is blown/ not connecting in it's holder/ corroded. The brake light is not powered thru' the taillight fuse, so thats why it still worked and with the key in 'park' position the taillight is powered by the main fuse, not the taillight fuse..... 

[n8dogg2000g]

The actual fix is that the taillight fuse is blown/ not connecting in it's holder/ corroded. The brake light is not powered thru' the taillight fuse, so thats why it still worked and with the key in 'park' position the taillight is powered by the main fuse, not the taillight fuse..... 

This is not true for my 76 CB550 (which I believe is relatively stock..but who knows).  If the tail light fuse is blown, the tail light will not light in the 'on' or 'park' position, but the brake light will light.  I had the same issue as msalgado44, the fix was retracing the wiring inside the headlight.  The previous owner had several black wires hooked up to the wrong connector (there are two separate connectors for the black wires that have to be correct for the tail/tach/speedo lights to work).

[bollingball]

Better 7 months late than never