Electrical problems, No headlight

[Mitch81special]

1981 special SH. So Iv been reading through other posts on this issue and I'm still coming up empty. The problem is iv got no headlight, no highbeam light and no backlight on the gauges. Charging system seems to be working. Now I think the yellow wire from the stator powers the headlight right? Right out of the stator I'm getting about 6 volts in DC is that right? Iv also got continuity. But I get no voltage at the headlight. Also wondering if this is a relay problem. I found a relay on ebay but the numbers on it are different, would it still work? Any help is greatly appreciated.

 

[gggGary]

There is the starter/headlight relay and the reserve lighting unit. If the gauge bulbs aren't blown (common) then the headlight fuse might be your issue.
The special fuseboxes are known bad actors, the little clips that hold the fuse look OK but typically crumble when disturbed. Not too hard to replace the fuse box with a more modern ATO type box.
that yellow wire should show about 5-6 volt AC. It closes the relay so +12 from the battery can power the headlight.

 

[xjwmx]

Like Mel Tillis says, the 6v on yellow is right. It's to power a 6V relay to switch 12V to turn the light on. First check that you have 12V at the headlight socket. If you don't, check the BL/B for 12V from this diagram:

If no 12V there and 12V on the other side of the relay, the relay is bad. You can find a new one, or you can bypass it, like here:
http://www.xs650.com/threads/good-headlight-mod-for-special.50722/#post-527644

If no 12V on the input side of the relay, download a wiring diagram and see if the headlights and gauge lights have anything in common, to start with. These are very straightforward to diagnose. Not like a modern car which has computer upon computer there to render your meter useless...

P.S. Updated: I told you to check the wrong wire, is fixed now

 

[Mitch81special]

So it turns out my starter lockout/headlight relay was bad. I got a new one off ebay and problem solved!
Thanks for all the input everyone.

 

[jackhenryfin]

Hello, I am currently running into electrical issues with my 1980 xs650 special, I am reassembling the bike and I went to check if the headlight works and it doesn’t. When I bought the bike it worked and now all of a sudden it will not turn on in any circumstances. I recently wired new blinkers as well, the worked when I first put them on, the next day they wont work at all and the left blinker won’t work whatsoever. My thinking is on of the 2 relays, I’m getting practically zero volts at the headlight and I am getting 3 volts out of what I think might be the stator, it is a yellow wires that comes from under the bike somewhere to a braided yellow wire that connects to another yellow wire that runs to the headlight. I’m guessing that 3 volts is not near enough to power the headlight and I only get about .3 volts at the headlight. I did just replace the regulator because the old one was bad, and I recently took the headlight housing off to paint it, but as I labeled and took pictures I’m pretty certain all the wires are connected good. Any suggestions?

 

[gggGary]

Is the bike charging? IE M/L 14 volts at 3,000RPM 13 volts at fast idle. The headlight will light ONLY if the alternator starts charging.
Not charging is my first guess.
Blinker issue there's' two common problems
#1 the black DARK green and DARK brown wires are easily mismatched in the headlight bucket.
#2 the solder blob wire connections inside the left handlebar turn signal switch often just fall off. A very easy fix, nearly anyone that can hold a soldering iron repairs that one in the wink of an eye.

 

[jackhenryfin]

How do I need to check the charging system, I’m new to motorcycles and suck with a multi meter lol.

 

[gggGary]

red on battery +12 terminal black on battery ground set meter to closest voltage but great er than 20 volts usually 20 volts or autorange if you have that setting start bike and watch;
idle; 12 volts plus , fast idle; 13 volts plus , revved to 3K; 14 volts plus, report back.

 

[jackhenryfin]

It stays in between 19.5 and 19.7 I had the red prong to the positive and the black prong to the negative. That seems scary high

 

[gggGary]

It stays in between 19.5 and 19.7 I had the red prong to the positive and the black prong to the negative. That seems scary high

there are two different volt settings AC and DC, you might be on the AC range?
this is a DC system.

 

[jackhenryfin]

this is my multi meter

 

[jackhenryfin]

The setting it is on is what I had it on

 

[gggGary]

That looks like the correct setting, what do you get with the bike off?

 

[jackhenryfin]

19.7 ish

 

[gggGary]

Well somethings odd cuz the battery should show 12.8ish ignition off.
When's the last time you changed batteries in the VOM?

 

[gggGary]

Just for giggles try it on the 200 volt setting.

 

[jackhenryfin]

About 20v off, 19.7 at idle, and 19.7 at 3k on the 200 setting

 

[gggGary]

Well A you need a new meter or batteries in it.
B Even with it's odd readings it's prolly saying it's not charging.
Is it charging? 101: watch ANY light bulb on the bike, like the tail light or brake light does it get brighter when you rev the bike?
If not it isn't charging. Why did you replace the voltage regulator?
Many of us have a voltmeter wired in where we can see it while riding.

 

[jpdevol]

About 20v off, 19.7 at idle, and 19.7 at 3k on the 200 setting

Well, that kinda indicates it's not charging......but, you're gonna have to get that meter fixed or find a "known good" meter so ya can get reliable readings...

I did just replace the regulator because the old one was bad, and I recently took the headlight housing off to paint it, but as I labeled and took pictures I’m pretty certain all the wires are connected good. Any suggestions?

What regulator did you use to replace the original?

 

[jpdevol]

And....the yellow wire with the cloth insulation does work the headlight through the safety relay and its output is ~ 5VAC - so that part of the stator appears to be working (maybe) The safety relay closes a circuit from red/yellow (12VDC) and powers the blue/black when the engine starts