no power to headlight, cant trace problem

tbakic · Apr 7, 2012

hey guys, im finally working on my cafe project again, trying to get my headlight working :banghead:

, i got a new fuse/fuse holder, i tested here for power and got nothing

also in that pic im assuming like color wires go to themselves, but what about the blue wire coming from the headlight/turn/horn assembly? does that go in to the dual yellow plug on the light or???

anyway no power there, then i tried one plug back at this one, same thing no power anywhere

then i tried putting continuity on the out end of the fuse and i found instead of going to that big plug, i got it in the plug for the flasher relay right here

now im assuming i need the flasher relay plugged in and then the power will get sent out down to the headlight, but i dont have a flasher relay, if this really is the problem can i go without the flasher realy(as im not using turn signals) and just cut that plug out and splice the wires together, if so which ones?

thanks guys.

p.s if anybody wants to assist me in rewiring my front end that would be sweet, as a few wires are broken and every wiring diagram i look at is confusing as all hell to me, i can supply detailed pics for anyone willing to assist me, thank u so much

drewpy · Apr 7, 2012

I think the blue goes to headlamp switch!

tbakic · Apr 7, 2012

do you mean like the hi/low switch?

arfstrom · Apr 7, 2012

Check to see if you have charging. there (certain models) have to have more than 10 volts or so to activate the relay power to the head lights. Possibly a safety relay, and next to it is the headlight relay, (certain models) right there under the battery tray, forward of the battery. under the breathing manufold (thing connected to the airfilters)
Good luck, goto go!
Tobie

tbakic · Apr 7, 2012

oh yeah my model is a 1980 xs400 special

ThePsuedoMonkey · Apr 7, 2012

From headlight switch:
Yellow should go to the high beam and it's indicator light. Green to low beam. Blue to gauge lights and is fed power from the safety relay on the headlight circuit. The brown on the flasher relay is tied into the main power, so it does normally have continuity with any of the red+white and red+yellow wires (pretty much everything). Like arfstrom said, the safety relay is probably where your issue is tied up at; that relay needs power from the alternator to trip, then it can send power from the headlight circuit to the blue wires.

HoughMade · Apr 7, 2012

You are aware that the headlight will not get power until the engine starts, or at least fires?

tbakic · Apr 7, 2012

I was not aware the engine needed to b started...lol

scruftdog · Apr 8, 2012

I learned that the bike had to be running from the forums also ... so dont feel bad.
I was at the same spot you are, I though I had a bad relay..

tbakic · Apr 8, 2012

Out of curiosity can anyone post a pic of this headlight relay?

Ebola Monkey · Apr 8, 2012

It's on the right side mounted to the horizontal cross brace, under the side cover.

Mine's also an 80 special.

arfstrom · Apr 8, 2012

Here is the 81 xs400SH (4R4) diagram, its in 2 parts cause its too big for my scanner and I havent figured out how to combine it yet, out side of using tape, and folding it right.

Tobie

ThePsuedoMonkey · Apr 9, 2012

As a "thank you" for providing me with that schematic...

arfstrom · Apr 9, 2012

Your welcome, I was hoping this would give tbakic a easier way of saying this relay is the safety, and that is the other relay. That is really a great job of color-izing!
Tobie

tbakic · Apr 11, 2012

ThePsuedoMonkey said:
As a "thank you" for providing me with that schematic...

WOW! thanks holy crap, every diagram ive seen isnt the right one..untill now!!

tbakic · Apr 11, 2012

Ebola Monkey said:
It's on the right side mounted to the horizontal cross brace, under the side cover.

Mine's also an 80 special.

thanks for the pic! i defiantly do not have anything mounted there...i do have something that looks like that up front by by forward gas tank mounts i could get a pic of and then we could see if thats it, i cant quite tell by this picture if i did indeed find it or not.

Jimbo31 · May 1, 2013

was there any solution to this problem? My problem seems very similar and that stupid blue wire confuses me cuz its not on any diagrams

dgaige · May 14, 2013

That wiring diagram is a life saver. I have an '83 400 XS and had a vexing headlight problem. Got it solved.
Thanks

camalot400 · Jun 3, 2013

Hello, im having thesame problem, can any one show in a pic, where I fi.d the headlight diode? Thanks alot!

dgaige · Jun 3, 2013

I went thru my '83, and found no diode. The relays were the problem, combined with poor electrical connection to the new headlight. I had to clean off the contacts a couple of times to get a reliable connection. Did you try bypassing the relay to get power to the headlight all the time?

no power to headlight, cant trace problem

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