Help with Electric Issue

[txtriathlete]

So, had my 80 SG out on the road the other day, and now having an electrical issue. Disclaimer - I am an average good mechanic but not great with electrical troubleshooting.

The issue is that the indicator lights (neutral, oil, etc.) don't come on, signals don't work, brake light doesn't come on when lever is squeezed or pedal pressed. Tach is dead.

Bike starts and runs fine. Tail light comes on when the key is turned on, headlight only comes on once the bike starts (taillight stays on while running). Speedo and tach lights come on once the bike is started but not with key turn. From the wire diagram It looks like the headlight, taillight and speedo/tach lights are all run from the reserve lighting, which would explain why I have these and no others, but doesn't tell me where the rest of the system is failing.

The electrical system itself is pretty clean, hasn't been hacked up or modified. I installed an original style headlight when I got it, it had a fairing light bucket installed on it, but other than that no mods. After power went out I checked the fuses, the turn signal fuse was blown, I replaced it but nothing came back.

Thinking this has to be something like a relay or a common ground issue that would affect all the lights. Is there another main fuse somewhere? Can't see anything in the manual that addresses this type of problem and I can't trace the electrical diagram to a common source point. Everything was working when I left on the last ride, so maybe something shook loose or got overloaded?

Thanks!

[soccer4m]

WHere is 3Phase or DiverRay?

Maybe 3Phase or DiverRay can chime in on this electrical problem,,,they have mucho experience in this kind of dilemna.................Mike in Sun Diego

[Ranger_xs1100]

fuse box?

I recently had the same problem on the 81LH that I am working on. It was a troubleshooting challenge, but what I found was that the fuse box was the problem. The fuse holder spring clips have lost their tension or have corroded and are no longer conducting. Specifically the 20 amp turn signal fuse holder. You’ll have to check the voltage on the wires themselves coming into and going out of the fuse box terminals, not on the fuse itself. Replacing the fuse box brought back my green neutral and red oil pressure lights as well as the brake lights and turn signals. A sure way to test this theory is to jumper in a 20 amp fuse with a couple of alligator clip jumper wires, but again, not on the fuse or fuse holder itself, it has to be on the wires coming in and out of the fuse box.

[txtriathlete]

Good thought. My fuse block is pretty cruddy, I had it on the list, maybe now is the time to change it over to blade fuses. I'll try jumping the leads and see what I get. Thanks.

I recently had the same problem on the 81LH that I am working on. It was a troubleshooting challenge, but what I found was that the fuse box was the problem. The fuse holder spring clips have lost their tension or have corroded and are no longer conducting. Specifically the 20 amp turn signal fuse holder. You’ll have to check the voltage on the wires themselves coming into and going out of the fuse box terminals, not on the fuse itself. Replacing the fuse box brought back my green neutral and red oil pressure lights as well as the brake lights and turn signals. A sure way to test this theory is to jumper in a 20 amp fuse with a couple of alligator clip jumper wires, but again, not on the fuse or fuse holder itself, it has to be on the wires coming in and out of the fuse box.

[txtriathlete]

UPDATE: yep, bypassed the fuses and function is back (mostly). Will replace the fuse block tomorrow. Thanks Ranger!

New problem - now that it's back up and working, the right turn signal doesn't flash, but the neutral light, oil light and tail light flash instead when I use the right indicator. Left signal works as it should. Thinking this may be what caused the signal fuse to blow. I'll spend some quality time looking though connections and comparing them to the diagram tomorrow. I hate electrical...

[Ranger_xs1100]

UPDATE: yep, bypassed the fuses and function is back (mostly). Will replace the fuse block tomorrow. Thanks Ranger!

New problem - now that it's back up and working, the right turn signal doesn't flash, but the neutral light, oil light and tail light flash instead when I use the right indicator. Left signal works as it should. Thinking this may be what caused the signal fuse to blow. I'll spend some quality time looking though connections and comparing them to the diagram tomorrow. I hate electrical...

Try switching on your 4way hazard flashers. The switch may be very stiff from many years of non use. If you find all 4 signals flashing, the problem is likely to be with the 3 prong signal flasher or possibly the auto cancel unit. I think that unplugging the auto cancel unit would eliminate that as a possibility.

If all 4 signals are blinking then you can swap the 2 prong hazard flasher with the regular 3 prong flasher as a test. But If you still have one side not blinking when the hazard switch is turned on, then I would suspect grounding issues to one or both of those 2 non-blinking signals.

On my 81LH, The hazard flasher is located on top of the frame, just forward of the battery, the regular 3 prong flasher is located under the right side cover below the fuse box. Not sure if it is the same on your bike.

Hope that helps!

[MaximPhil]

Hi txtriathlete,
As no one has mentioned yet. The headlight ONLY comes on once the bike is running,with a latching relay. If still original unhacked wiring.
Cleaning contacts is a constant on these old bikes. Upgrading the fuse panel is highly recommended.

Phil

[txtriathlete]

Update:

Went though the fuse panel today and swapped it with bladed fuses, so that one is fixed.

Got three of the four lights to flash with the hazards, rear right is not flashing.

Chased the connection and it's in the bulb housing - OWS (old wire syndrome). Looks like the contact base that connects to the bulb wasn't firmly contacting the bulb base. Old plastic yada, yada. So tomorrow will replace the light socket and see how that goes. Should fix the issue.

Quite a pain to get a wrench on that light stalk bolt under the fender.

Many thanks for the great advice!

[thumperjsa]

Had the same problem on 79 special recently. Also affected my tach as well. Same issue with bad fuse block. I'm replacing mine like I did on my 80G.

As to the flash, old wiring, bad ground will affect like you found it.