Topic: Brake/Tail light won't work

[XJrusso96]

76 cb400f,  when I got it most of the wiring was a mess.  But as far as the brake/tail light goes all the wiring seems intact and connected properly but I can't get it too work.  I have checked the bulb and fuse and they are both fine. Anyone have a similar problem or any ideas as to where to start?

Thanks

[dustyc]

My tail light was working intermittently and it turned out to be some corrosion on the connectors in the headlight bucket rather than the ones under the seat.   

[KingCustomCycles.com]

Connectors and switches routinely corrode and fail, wires less frequently.  Pop the seat and clean all those socket connections and then take out the headlight bezel and clean all of those connections.  Next step would then be to either trace down the offending wire or run a new one to a convenient key controlled positive.  I use scotch brite, LPS contact cleaner or ACF-50, or corrosion-X as needed on all connections of everything I own.  I did a jeep Grand Cherokee once with a 110 pin firewall connector and 21 onboard computers.  Electrical problems were then the least of its problems.   

[Hush]

Make up a "hot wire" from a known power source, the battery postive is best, then test the wires under the back of the seat.
If you get a tail light then problem is further up the line so follow the wire and keep checking with the hot wire until you find your dead spot.
Hey its a cheap and cheerful way to find your problem.
The foot brake operated switch can be a problem too so make sure it is adjusted enough to actually work, too much slack and contact will not be made.
Not sure if your bike has hand lever operated brake light but I find that the wee switch and wires tend to come loose occasionally and just a push back in works.

[XJrusso96]

HOW did you check the bulb and fuse? Visual check is not proof. Recommend a multimeter check of the bullet connections under the seat to verify whether power is getting to the taillight housing at all. If yes, then clean the bulb socket with terminal cleaner and replace bulb with brand new one(unless you can test the existing bulb in another bike or car or with jumper wires.)
 If no, Dustyc is right, connection problems behind the headlight can be the culprit. You should have a schematic to track the power path, but it's not rocket science. KCC is right, too, but I hope you don't have to run new wire. Like he says, connections and switches are the weak points. Are you getting headlamp? Turn signals?

Well I checked the bulb simply by connecting wires to it and touching one to the positive terminal and grounding the other, and for the fuse I never really checked it I just replaced it and tried a couple different brand new ones.  But it looks like cleaning cleaning all the connections did the trick cause its working fine now,  thanks for the help guys!

[KingCustomCycles.com]

"cheap and cheerful" I like that