XS1 Headlight Issue

[Zeus87]

Finally getting things finished up here on my XS1, and hoping to get it ready to pass NYS inspection. Everything works except for the headlight and the horn.. With the ignition switch clicked over all the way to the right, the tail light is on in which I would assume the headlight would be on as well? Well, if that is the case, than obviously I have no power running to the light. I put a meter on the headlight bulb socket (green, yellow and black wire) and found no juice running to it. Any suggestions? The horn also doesn't work, but that Is a mechanical issue as I have yet to find a button for the original horn control. Any suggestions as to what I should try next? Blinkers work, tail light, break light works, as well as neutral and blinker indicator light. Thanks in advance for all of your help.

 

[retiredgentleman]

The ignition switch has one position that powers the tail light only. It has another position that powers the tail light and the head light. Try selecting the different positions. The power to the head light flows from the ignition switch to the hi/low dimmer switch, so check for voltage at the dimmer switch. I assume you have checked the head light bulb itself.

 

[Zeus87]

You called it! Short in the dimmer switch. Thanks a bunch!

 

[wilbur60]

I know this is an old post, but... I have a similar problem. My headlight just went out last week. I made a hotwire from the battery to it and the headlight works. I have taken the dimmer switch apart and I really do not know how to check it. I used a light tester but did not get any indication there was power at the switch. I do not know how to isolate that switch, bypass it or test it.
I assume if I am not getting power to the switch then I am likely not getting power from the ignition, correct.?
Bill

 

[Grinder]

What year is your bike? Newer bikes have a safety relay that doesn't allow the headlight to come on until the bike starts. Is your charging system working correctly?

 

[wilbur60]

It is a 1980 xs special. I have never had a problem until last week. My headlight just stopped working. Everything else works fine. I direct wired it to make sure the headlight was ok. Since then I have wired it direct from the starter/ignition switch, thereby bypassing the dimmer, and it seems to work ok. I have checked the wires which run to the dimmer (in the headlight cavity) and they have power. I cannot get any indication there is power at any point in the dimmer switch. But then I do not know which wires/points should show a current and which should not. I assume it is the dimmer but do not know how to check it. It seems like I should be able to crosswire it so that it would work on either high or low beam, but do not know how to check it without cutting wires.
As I said, I have wired it direct to the headlamp from the ignition wires and it works fine, except I have no dimmer switch.
My question now is:
1. How do I test the dimmer switch, short of replacing it for 60 bucks.
2. How can I cross circuit the dimmer to isolate it, therefor isolating the problem.
Bill

 

[Grinder]

The blue/yellow wire is the feed into the dimmer. When you flip the switch to low beam the green should be hot, hi beam the yellow should be hot. I strongly suggest you throw a volt meter on your battery and make sure your charging system is working. There is a yellow wire that comes out of the stator that goes to the safety relay. When the charging system is working it sends power via the yellow wire to the safety relay and allows the headlight to come on. No power, no headlight. It should be charging at 14-14.5V at 3k rpms.

 

[XSLeo]

Those test lights only show if power is there. They don't show how much voltage is there. The best thing you can do with that test light is to walk out to your back fence and chuck it as far as you can.
Now go get a multi-meter. As Grinder said you need to be able to test voltages. Knowing the voltage to within .2 to .4 volts is often needed to know if there is a problem.
At the blue/yellow wire you should have a voltage reading the same as battery voltage. On the green and yellow wires when in the proper position should have battery voltage also.
The dimmer switch can be removed from the switch housing, this lets you inspect and clean the contacts inside the switch. Bright and shiny is a good thing. A very thin coat of grease will help prevent corrosion. Dielectric grease is best but most any light grease will work.
Leo

 

[wilbur60]

Well, I finally had some time to address my headlight issue. I took things apart, cleaned the switch and it worked. Must have been the switch.
Thanks for the suggestions. The diagram really helps, too.
I want to check the charging system but do not know where the stator is. I assume that is the starting point. I do have a voltmeter to check the voltage.
It would be nice to know if the charging system is working correctly. I do not want anymore surprises when I am riding away from home.

 

[Grinder]

Check your voltage at the battery first. It should be about 14-14.5V at 3k rpms. Stator is under the round cover on the left engine side cover.