Topic: ..no headlight/taillight. HELP!!

[drackett_19]

Hey guys, i think this bike has more wiring than a space shuttle. Hoping somebody can help me out, i'll provide as much detail as I can. Bike is a 1975 cb550K. (without the headlight on/off switch)

The headlight started cutting out periodically (i assume taillight was too but i couldn't see it) then both quit working entirely. Bike still runs fine and the brake light works when pedal pushed, but no running tail light.

Found that my Emgo ignition switch wires were toast..melted up and looking terrible. So I ordered up a new one and still having the same problems.

What I find really strange is that when I test the 4 wires coming out of the ignition switch, the brown/white wire doesn't have power in any key spot (3) (off, run, park)

in OFF- RED wire is hot and the third fuse (furthest right) has power
in RUN- RED and BLACK wires are hot and 3rd fuse has power
in PARK- RED and Brown wires are hot and 1st and 3rd fuse are hot.

shouldn't the brown/white wire be hot when key is in the RUN position on the ignition switch?

I have a custom tail light and mini signal lights, but the signals still work fine and the taillight wires are nice with good ground.

Went over the wiring in the headlight and checked all the connections and they look fine.

Any advice or ideas are appreciated...this is getting pretty frustrating.

thanks!!

Dan

[Spanner 1]

So, brown/white wire gets it's 'hot' from the black at a connector in the headlight shell.... the brown/white wire-end should have a black ring on it to show it goes to black... is that good?... this brown/white supplies voltage to the the speedo and tacho lights and the tail-light....

[Gaither]

19

FWIW [I ain't an "electricutionist" by any stretch - I hate wiring and know nothing.

However, I lost the headlight and left front turn sig ['77 CB550F]. EVERYTHING else worked properly. [I had lost only the tail light immediately preceeding this the night before.]

Popwood [and several others] came on and had me run a new ground wire which I spliced into one of the grounds soldered to each internal headlight mounting nuts. I ran it to the bolt that secures the coils to the frame. It solved my problem. Great bunch of guys here!!

This may not solve your problem. However, it only takes a few minutes and, if it doesn't help, it will hurt nothing  to leave the new ground wire installed.

If your bike is like mine, the headlight will not come on unless the engine is running.

'Hope this helps.

[drackett_19]

Thanks a ton for the replies.

So, brown/white wire gets it's 'hot' from the black at a connector in the headlight shell.... the brown/white wire-end should have a black ring on it to show it goes to black... is that good?... this brown/white supplies voltage to the the speedo and tacho lights and the tail-light....

Okay, good to know. I tracked the brown/white wire into the headlight shell and it branches off into 3 places: tacho/speedo/and left control lever with hi/lo beam,signal lights,horn inside it.

it doesn't plug into a black wire anywhere but has a brown/red wire spliced into it early on in the wiring harness. the brown/red carries to the rear of the bike into 1 of the large plugs under the sidecover.

Gaither, thanks for the tip. I soldered in a ground to the shell bolt and still no lights, but you can never have too many good ground wires. Now that you mention your headlight only comes on when your bike is running, i'm going to focus more on getting the tail light working. Its strange, the brown wire that goes from the ignition straight to the taillight also has no power in the RUN position.

Thanks again for all the help and please fire any more ideas this way....gotta be something simple that i'm not seeing...


Dan

[drackett_19]

hey Spanner, should i just splice the brown/white wire into a black in the headlight shell?

[phrige]

Hey Drack, watching this thread intently since i have nearly the identical problem.

I did jump a black into the brown and white for a while in the headlight bucket and got brake light, headlight and front turnsignals (no rear) But I don't believe jumping the connection is a stock setting. I'm trying to figure how to get proper power into that circuit.

 I gatta recheck my emgo ignition see if thats whats killing the voltage in my brown and white circuit. Right now I'm getting 0.45volts in the 1st position ON mode.

I'll prob do a "Popwood" style ground as well, like you said cant have enough solid grounds.

[Spanner 1]

Yes, I would mate the brown/white with a black in the headlight shell as b/w gets it's power from black with ign. on it's first 'click' ( ON ).
When you do that there should be power on the solid brown ( switch 'ON' ), which is the tail-light.

[phrige]

Yea rereading my schematics I realized my problem is that I went to non-stock controls. which is what I forgot was the reason I jumped it originally.  Thanks.
 
Drackett, are you running stock handlebar controls? Could check continuity on the headlight on off switch which delivers power to things. Or just jump it in the bucket like Spanner suggestions and now I've re-instated.

[drackett_19]

Yes, I would mate the brown/white with a black in the headlight shell as b/w gets it's power from black with ign. on it's first 'click' ( ON ).
When you do that there should be power on the solid brown ( switch 'ON' ), which is the tail-light.

I did jump a black into the brown and white for a while in the headlight bucket and got brake light, headlight and front turnsignals

Okay thanks alot guys, just at work for the day but i'll give this a shot tonight.

Drackett, are you running stock handlebar controls? Could check continuity on the headlight on off switch which delivers power to things.

Yeah i'm still running the factory controls and my bike doesn't have an on/off switch for the headlight. But if the splicing doesn't work I might pull the controls apart and check for continuity...i know they're prone to wear out.

Like you mentioned Phrige, the splicing doesn't seem like the proper fix because it wasn't spliced before and worked fine up until the lights started cutting out on me. But i'll give it a shot...

[vern401]

Check the headlight switch. Make sure it is getting power from it's sorce. Some do not get any power until the bike fires. There should be a relay for this type someplace. Check the wiring diagram though I may be wrong about the relay but it would make sence.

[drackett_19]

Hey thanks spanner! i spliced the black and brown/white wires together and everything lit up as it should...no blown fuses or smoking either!    I'm still weary that its the right fix, so i'm going to check the headlight switch like you mention Vern, but it seems to be working great for now, took it out for about an hour ride last night without at hitch.

Thanks again everybody, this forum rules.