Topic: CB400F USA Tail Light Question

[Bristledisk]

Hi All,

I just replaced/re-wired the after market rear light installed by the previous owner with the original standard rear light on my 1977 CCB400F model. This is the USA model with no light switch above the starter button on the handle bars.

With the engine off:

CASE 1:When the ignition switch is in ON, the headlight and front turn signals are ON but the tail light is OFF.
CASE 2:When the ignition switch is in P, all lights are OFF except the rear light which is ON.
CASE 3: When the ignition switch is ON, and the front brake is applied, the rear light turns ON as expected.

I've no USA owner's manual but with no Head Light switch on the handlebar controls, when should the tail light come ON?

[Bodi]

In the ratsnest bunch of wire ends from the harness under the tank you will find a brown/black wire (brown with black stripe). Jumper that to the black wire in the same bunch of ends from the harness. That should fix your problem. Hopefully you have some odd harness parts lying around to make the jumper, it's male-male I think.
This is from Honda removing the headlight on/off switch. They included this jumper - a black wire joined to a brown/black wire - in the original USA switchpod harness (although it was rather easy to pull the thing out and have a "what the heck is this for" moment when it's found after putting everything together). Replacement switchpods do not have the jumper.
If that jumper is in place, check the TAIL fuse. The power path is rather confused for the tail light: it's powered through the TAIL (and MAIN, in fact) fuse when the key is ON, through the MAIN fuse alone in "P".
A problem with the keyswitch can also cause what you have.

[Bristledisk]

Thanks Bodi. The Tail fuse was the culprit. I'd never of guessed that as the rear light worked in "P"

[Deltarider]

When the ignition switch is in ON, the headlight and front turn signals are ON

If that is the US wiring I'm glad we didn't have it overhere. What idiot thought it wise to have the lights switched on before you have even started the engine, where you need all the battery power. It's crazy.

[carnivorous chicken]

Some states in the US mandated daytime headlight use in 1975. Analysis showed a decrease in fatal accidents. Why they couldn't have enforced the law AND had off switches for headlights I do not know. Must be the headlight manufacturing lobby (just jokes).

But the bikes have an override switch that shuts off the headlight while the starter is cranking, so all the juice goes to the starter. At least the CB200 I worked on the other day was like that.

*** I should add: some states still don't have mandatory daytime headlight use, such as Arizona. And others, such as Massachusetts, grandfather old bikes so that if they're pre-1975 you can ride during the day without your headlight. This is mandatory for me and my little CB160 as the charging system on that thing is weak.