No power going to headlight, chasing wires everywhere

[Hender107]

Im hoping someone can tell me what color the wire that supplies power to headlight is? I assume blue with a black stripe? I am doing my best to decipher the wire diagram I have , this is what I cam up with.

1. power comes in from blue/black wire and goes to hand switch
2. comes out of hand switch as yellow wire and green wire and goes to head light
3. second yellow goes from light to high beam indicator

Ive checked all my grounds and have clean connections, and I'm ruling out and problems with my switch given I don't have any power even going to it.

Chasing the blue wire back, I found a broken diode on a white wire along the way and ultimately followed it back to the relay where I have power coming in on a red wire and nothing going out, is it safe to say I've found my problem? Also I read on another thread the white wire diode also sends power/is related to the headlight?

Any other suggestions or info you can share with me regarding anything headlight related please do, or just let me know I'm headed in the right direction.

 

[Wolfe_11B]

If the diode is broke, the relay will never turn on, therefore never supply power to the headlight. I think you've found your problem!

 

[Hender107]

good to know, I ordered the diode already so good to know that will be needed. Any idea how the white wire plays into the headlight? does that also send power to a relay or something. Im just trying to get a good understanding for what all is going on. Thanks in advance!

 

[Wolfe_11B]

The white wire and diode provide the power to make the relay activate. The relay then latches itself 'on' and allows the red/yellow wire to feed power to the headlight(and others) through the blue/black wire.

The whole point is to have the lights off automatically and then turn them on once the stator is producing it's own power. Easier to start the bike this way as there is no draw on the battery except for the starter.

 

[Hender107]

Gotcha, thanks for the explanation. Maybe you can shed some light on this also, I read on another thread the bike had to be running for the headlight to come on and also in order for the flashers to flash. Coincidentally I have that problem at the moment also and im not sure of the truth as the bike isnt quite running yet.

 

[BBS360]

Not 100% sure about the flashers without the wiring diagram in front of me, but yes, that is the purpose of the white wire, diode, and relay.
The headlight circuit does not receive power until the motor is running and the stator powers the relay via the diode and white wire.

Check out the wiring diagram, it shows the connection from stator, to diode, relay, and headlight.

 

[arfstrom]

Not 100% sure about the flashers without the wiring diagram in front of me, but yes, that is the purpose of the white wire, diode, and relay.
The headlight circuit does not receive power until the motor is running and the stator powers the relay via the diode and white wire.

Check out the wiring diagram, it shows the connection from stator, to diode, relay, and headlight.

Flashers will flash with key on. Like Wolfe said, we have a relay, that is looking for a signal from the stator. now with that said, a stator spinning, will generate just enough power, to preempt the starting system. So if your signals are bad, start with the fuse first approach. Then dig deeper. (grounds next)

 

[Wolfe_11B]

Yep signals and tail light should come on with the key.

Another thing to note, if you have a weak battery it may affect the flashing while the bike is off

 

[Hender107]

If I had a ground or fuse issue wouldnt they not come on at all? When i flick the switch they come on, relay makes a funny noise and then they just stay lit, 3 different relays and they all did the same thing, make the same noise and everything. Am i just that unlucky and got 3 bum relays or should i be looking elsewhere?

 

[BBS360]

We're talking about your flashers? As Wolfe suggested, low voltage could cause unreliable operation of the flasher relay.
What's your battery voltage at?
If we're talking stock flasher relays, they're all pretty old now. Even the supposedly "tested and good" stock relay I bought didn't flash properly.

 

[xs400newbie0584]

Can someone please tell me what color wires go where on the starter relay...not the solenoid... with the yellow painted post on the bottom and pins facing you.
Thanks!

 

[arfstrom]

Have you told us what bike you have?there is a differencee in pre 80, and post 82. Most of us have identified the bike in the signature, so that thier is no question.
With that said, there is a colored copy of the 80-81, listed in the wire diagrams. Seems there is nine pages, one of them should have your model of bike.
http://www.xs400.com/threads/yamaha-xs400-wiring-diagrams.4466/page-2

 

[xs400newbie0584]

Ok... And thanks... I will update my signature... It's a 81 special II 400...

 

[BBS360]

The relay with the yellow stub is the headlight relay.
The other similar relay is the clutch safety relay.
The starter relay is the solenoid.

Colours should be as per the attached diagram.

 

[xs400newbie0584]

Thank you! Got it all put back together and running! Now on to my idle issue... Reading threads now! Thanks everyone!

 

[Kosan181]

Im hoping someone can tell me what color the wire that supplies power to headlight is? I assume blue with a black stripe? I am doing my best to decipher the wire diagram I have , this is what I cam up with.

1. power comes in from blue/black wire and goes to hand switch
2. comes out of hand switch as yellow wire and green wire and goes to head light
3. second yellow goes from light to high beam indicator

Ive checked all my grounds and have clean connections, and I'm ruling out and problems with my switch given I don't have any power even going to it.

Chasing the blue wire back, I found a broken diode on a white wire along the way and ultimately followed it back to the relay where I have power coming in on a red wire and nothing going out, is it safe to say I've found my problem? Also I read on another thread the white wire diode also sends power/is related to the headlight?

Any other suggestions or info you can share with me regarding anything headlight related please do, or just let me know I'm headed in the right direction.

Did you fix it? I'm having the same issue.