driving at night and BOOM! no lights!

[dfinnegan71]

Yes this is true, it just happened last night.
First of all, thanks to you fellas who have helped me get my project 1980 GS 550 up and running.
Here's the story. Yesterday I took the bike to work for the first time. 27 miles each way. On my way there I noticed my turn signals were non-functional all of a sudden and I lost my gear indicator lights. No biggie I thought. On my way home I hit a bump in the road, a little hard mind you, and my headlight went very dim. But the very next bump, all lights out! NO headlight or tail light. I acutally rode it for the last mile like this...in the rain....at night. SCARY! STUPID! but EXILERATING!
Anyway, it figures because I did everything to this bike to get it running and rideable. However, I didn't touch the wiring because that was the one thing that worked when I got it. All lights were functional. I havent' had a chance yet to look at it, but it dosn't seem like a fuse problem...any ideas?

[koolaid_kid]

Sounds like ground issue(s) to me. Time to fire up the multimeter and start testing.

[Toasty]

Look for wires that have the insulation worn, even a little bit of exposed wire can ground out and pop a fuse. I had this issue for a while and it was just bad wiring. Also check the fuse box, I guarantee you popped a fuse. Either the bump jarred it and broke it, or it rubbed a wire somewhere and popped it.

[Guest]

Grounds are the biggest problem on these bikes second are the plug in connectors, take them apart and clean them up, remember you are working with equipment that is 31 years young

[MisterCinders]

Sounds like two fuses, lights and signals.

[dfinnegan71]

Lots of work to be done...thanks I'll get cracka lackin

[dfinnegan71]

First quick look in the fuse box revealed 3 of the 4 fuses blown. Main, headlight , and signals. The one that was OK.... Ignition fuse, thus why I made it home! Now to figure out why?

[koolaid_kid]

You have a short somewhere. Do you have a wiring diagram? There is some commonality between all of them.

[MisterCinders]

First quick look in the fuse box revealed 3 of the 4 fuses blown. Main, headlight , and signals. The one that was OK.... Ignition fuse, thus why I made it home! Now to figure out why?

Um, this cannot be correct.

You have a short somewhere. Do you have a wiring diagram? There is some commonality between all of them.

Check your diagram AND your actual wiring. If you blew the main fuse, there should be no power to the bike at all. If your ignition survived a blown main fuse, then your wiring is out of order. It should follow like so:

BATT (+) -> 15A FUSE -> R/R joins -> IGN -> FUSE BLOCK (3 x 10A) -> systems

If the 15A fuse was in the right spot, blowing it should kill the bike.

[koolaid_kid]

So, the other question that begs to be answered, is how was the bike turned off. If the ignition key was functional, that means that it was still getting power, which should not be possible if MAIN is blown.
Clarification is required.

[SqDancerLynn1]

Had that happen, There was a moon out and the turn signals still worked. Very little traffic. I rode about 10 miles without a headlight. Just hit the turn signals when needed for a little extra saftey

[Redman]

S............ that means that it was still getting power, which should not be possible if MAIN is blown.
Clarification is required.

......
..............If you blew the main fuse, there should be no power to the bike at all. ...........

....except from the charging system.

The charging system red wire ties into the main red wire inbetween the main fuse and the ignition switch.

If do not have the main fuse, what you dont have is a battery connected to the red wire that goes to ignition swtich, you still have the charging system connected to the red wire that goes to ignition switch.

So if bike is running and charging system functional, could pull the main fuse and the charging system is still suppling power (do keep up the rpms) to the ignition switch (and then to Head fuse, Ignition fuse and Signal fuse).
I have not actaully tried this, just looking at schematics.

.

[Redman]

dfin,

Your first description of loosing multiple decvices did sound like a goround problem.

First quick look in the fuse box revealed 3 of the 4 fuses blown. Main, headlight , and signals. The one that was OK.... Ignition fuse, thus why I made it home! Now to figure out why?

But now that you say multiple fuses have blow, that is more like a short circuit to ground on more than one circuit.

Go get a pack of 15 amp fuses (main) and a pack (or two) of 10 amp fuses.
(dont bother with those assortment packs, they have mostly ones you dont need, and not enough of what you do need.)

THe turn signal controller is in both the headlight fuse circuit and the signal fuse circuit. SO if looking for one device that coukld effect both fuses (and main fuse) you can suspect that. Try disconnecting it, replace fuses, and see if fuses hold when turn key on. If they do hold, try wingling around the main wiring harness (take off tank so can grab it better). Try wiggling especailly were the wiring harness goes around the frame neck an other places the harness is close to frame. Look for where the insullation may be worn away from wires or wiring harness.

I suspect more that someplace the wiring harness has rubbed against something and have multiple wires with insullation worn away.

Tell us what you find.

WHen you say blew fuse in the rain, I suspect the horns (they are powered all the time when key is on, the button completes the ground), but that is in the Signal circuit and would not effect the Head fuse. IF short to ground in a horn, it will blow fuse as soon as turn on key, which is the same as will happen with bare wire in harness shorted to ground (assuming it is touching ground at that time). But can easy disconnect the horns.

Again, I suspect someplace on wiring harness has insulation worn away and bare copper grounding to the frame somewhere.

.

.

[Redman]

dfin,

I might suggest that you Put your general location in user profile (User CP).

Dave

.

[koolaid_kid]

....except from the charging system.

The charging system red wire ties into the main red wire inbetween the main fuse and the ignition switch.

If do not have the main fuse, what you dont have is a battery connected to the red wire that goes to ignition swtich, you still have the charging system connected to the red wire that goes to ignition switch.

So if bike is running and charging system functional, could pull the main fuse and the charging system is still suppling power (do keep up the rpms) to the ignition switch (and then to Head fuse, Ignition fuse and Signal fuse).
I have not actaully tried this, just looking at schematics.

.

That's true. Doesn't it Y into the red wire somewhere under the tank?
Then it would go back to the fuse block to hit the other 3 fuses. 2 blew, but the ignition one stayed intact, thus powering the ignition system.
I actually downloaded and printed out his wiring diagram, but I did not have an enlarger to blow it up to readable size.