Headlight issue

inbrick

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I have a 1980 special II (g) that a friend of mine was kind enough to give to me. He lost interest in motorcycles (I'm not sure how that would happen), and said I could have the bike if I promised to get it working. It had been sitting for over a year and was in rough shape, both mechanically and aesthetically. I took it to a shop to get the tank and carbs cleaned, battery charged, etc, and it runs now. I've had it for about 9 months. Still needs lots of work, and I don't have the skills to fix it myself or the money to pay for it to be done, so I've been addressing things as they become unbearable.

A couple months ago I was having issues with my headlight, turn signals, and horn. The fuses for the turn signals and headlight kept on blowing. When they fuses were intact, the headlight still wouldn't work and only my right turn signal would light. The horn would work if the fuses were intact. I figured out a couple weeks ago that the clutch-side switch was the source of the problems, and bought a replacement from mikesxs. The fuse-blowing problem is now solved, the turn signals work, the horn works, and my headlight works, but not quite right. The electric starter works fine, and I have never had any problems with my battery not charging, so I do not suspect the alternator or charging system.

When the switch is on low-beam, the light is very dim - too dim to cast any light beyond about a meter. The blue "high beam" indicator light on the instrument panel is lit very dimly. 8 volts flowing on the yellow wire to the headlight, no voltage on the dark green.

When the switch is on high-beam, the light is slightly dimmer than I would expect a fully functional low-beam to be. The "high beam" indicator light on the panel is not lit at all. 24 v flowing on the dark green wire to the headlight, no voltage on the yellow.

As far as I know, all parts are either stock or as close as I could get to stock if I had to get replacements from mikesxs. The ground from the headlight has 0 ohm resistance.

I suspect there is a problem in the switch, as I think I should have voltage on the dark green wire for the low-beam and on the yellow wire for the high-beam. However, I didn't take any readings on the headlight when it was working properly oh-so-long ago, so I am not sure. Comments or suggestions?
 
I looked on the manual and IIRC I had a similar problem with my 83 I think your bike has both a lighting reserve unit and a headlight starter cutout relay. They are located behind the left? side cover. I would unplug them, check the connections and replug them. Seems like that was what solved my problem.
 
Thanks for the suggestion. There is a "safety relay" under the right side cover, which is actually two relays. One ensures the starter button is inactive when the engine is running, the other turns on the headlight after the engine starts and ensures the light does not turn off even if the engine dies. I recently replaced this relay with a used stock part from ebay.

The reserve lighting system is a grey box under the seat, near the battery. I have nor replaced this.

When I have tried checking connections on these two parts in the past, I was unsure how to do so, as disconnecting them makes the bike not able to start since the relay isn't in place. Could you give me more details on how I should check the connections? Sorry for the newbie questions...
 
Do you have a wiring diagram? I could email you one if it will help you. If I recall correctly you unhook that sucker and hook the blue/black to the blue / yellow.

Here's a simple way to trouble shoot part of this. As posted by a respected more experienced member - RG

Get yourself a jumper wire and connect one end to the battery positive. The reserve lighting device is a grey plastic unit that sits behind the battery. The RLD has a blue/yellow and a blue/black wire. Touch the jumper to the blue/yellow, if headlight comes on then your wiring is good through the dimmer switch to the light. If doesn't come on, then dimmer sw or headlight is bad. Also check that the black wire at the headlight is grounded properly.

If light worked OK, now touch the jumper to the blue/black wire, if light still working then the RLD is working.

Hope this helps. I'm just passin' it on.
 
I do have a wiring diagram that has proved helpful to me in previous electrical issues. Thanks for the offer, though.

Thanks for passing that information on, pumps. RG, if you ever read this, thanks much to you as well. I think the RLD might be the problem. The ground from the headlight is good.

The light worked perfectly with the jumper wire from the positive battery terminal connected to the blue/yellow wire. The dimmer switch acted the way I would expect it to. The light did not work at all with the jumper linking the positive battery terminal to the blue/black with the RLD disconnected. However, the light DID work with the jumper shorting the blue/black to the blue/yellow. Can I conclude that the RLU is the problem?

If it is indeed the problem, is it safe to bypass it by shorting the blue/black to the blue/yellow permanently? Everything seems to work ok like this, but I don't want to remove anything that is important. I understand the RLU is supposed to light the other filament if one of the filaments in the bulb burns out. I am willing to live with this. Is there anything else that I should be concerned about?

Thanks again.
 
Many of us go through a similar drill when it comes to what some call "The Bells & Whistles" of the specials.....self cancelling turn signal unit.....reserve lighting unit....light checker....the safety relay lights always on except for starting... the kick-stand down ignition cut out etc. Most importantly, let's not forget those infernal vacuum operated fuel tank petcocks. One by one these all go their way. Truth be told in old age these units can cause more problems than they were designed to prevent.

My:twocents:.....I like the "Specials" but I like them even more when their "Bells & Whistles" are long gone. When the roto-tiller handle bars are replaced with standard style. When the self-cancelling turn signal unit is replaced by my left thumb, the lights on or off is done by my right one on the "lights on/off" switch. The "light checking" by noticing that it's dark. I do like and leave the high beam indicator, the neutral indicator, the turn signal indicators and the safety relay as regards the starter motor. I also keep the kill switch.

The first time I by-passed all these and then traced out all the irrelevant wiring involved with these devices, I was struck with how non-intimidating the XS-650 necessary function wiring left really was and how appropriate the "Simpla Fi" moto could be. Sure makes a different looking scene inside your headlight housing and the pile of pretty colored wires on the floor like something to be saved for a peacock. :bike: Best, Blue
 
The problem sounds like a bad reserve lighting unit. They are available here on this site, just post up you need one & you'll get some response's. I, too, have a "G", and I burned up one, got one from somebody here for like $10.
Either that, or your headlite bulb is no good. Could be a burned out low beam filament. Can check it by pulling your bike into a shady spot,( less lite, not a crack house).Shine your high beam onto a wall & check where it hits the wall. Now turn the low beam on. Doe's the dim lite hit the same spot? If so, the low beam is gone. You can get a headlite anywhere, I think the # is 6054.
 
You might want to replace your fuse panel with inline blade type fuse holders. Those round glass fuses and the panel cause many problems.
 
I know this is an older post, however, can you just completely bypass the RLU? My headlight is still good and when i detach the dimmer switch and run a jumper from the green plug on the headlight straight to the battery, i get light. when i hook up the green plug to the dimmer switch i get nothing. when i jump the green hook up to the yellow wire that goes back to the RLU, i again get nothing. I am pretty sure that the dimmer switch is fine and the RLU is the culprit. any suggestions?
 
can you just completely bypass the RLU?

Yes, you can. Search 650garage.com. You just remove the unit and jump two wires in the plug together. I cut them about an inch from the plug to make it easier to reattach someday, and soldered the other two ends together. My RLU was working but I didn't know if it would fail due to age, leaving me with no headlight at all. In the middle of a curve on the side of a hill at night....
 
okay i will give that a try. what do i do with all the other wires?... just cap them off?
 
I jumped the blue and black and the blue and yellow wires together, however, still no headlight when started. now i am unsure where to go next.
 
You don't have to do anything with the other wires. I just unplugged the RLU, pitched it. I connected the blue/black and blue/yellow together, with a jumper wire, at the back of the plug. I soldered mine (be sure to insulate your connections). I left the plug connected and used a wire tie to keep the plug from moving around.
 
Ok, first off, is the battery getting recharged? Is the charging system working? You also have a relay that get's a signal from the charging system when the bike is running. On the left side, where all the wiring comes out of the cover, there should be a yellow wire all by itself. This wire will show voltage while the bike is running. This wire is the signal for the safety relay to close and allow the headlite to come on. If you jumpered out the RLU, blue/ yellow to blue/ black and no headlite, your trouble is possibly in that circut I described earlier. That relay and circut are for battery life. After 1979, all new motorcycle's had to have their headlite on all the time. The relay allows the headlite to come on when the bike is running. It's so the battery won't die because of the extra draw if the headlite was on while trying to start the engine. Check that circut, then see what's up. Do you have a repair manual? If not, go to Knucklebuster.com. Find and copy/print out the wiring diagram for your model. There are tip's there on trouble shooting.
 
What year is your bike..............there are differences in the wiring.
Gordon brought up a good point. Your alternator must be charging correctly or the Safety Relay will not work and you will have no headlight.

The bike is an 83' heritage. i haven't been able to test the rotor yet (work) however monday i am planning on going to the garage but i know that the stator is working fine now.
 
i have an 81 xs650 and yesterday my headlight worked but now it is no longer working. I looked through the glass and the bulb doesnt look broken(not too sure). Do you have any tips on diagnosing this issue?
 
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