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Old 09-05-2014, 06:10 AM   #1
meijer's trails OP
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hmm. what problem would stop all lighting on an 81 g/s

Before I start digging, I thought I'd take the easy way out by asking the forum.

Something happened that immediately stopped all the lights and tach. Yet the battery is charging and the starter works fine. And my red charging light is functioning normally( on with key off with revs)

Is there a connector or a fuse in common somewhere to the lighting system?

Thanks guys
Jason
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Old 09-05-2014, 06:29 AM   #2
Udo
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Here's the map.
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Old 09-05-2014, 07:18 AM   #3
Rucksta
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Check the three large red white & black under the tank right front.
Sometimes it helps to give them a bit of a wiggle.
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Old 09-05-2014, 07:29 AM   #4
Beater
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Quote:
Originally Posted by Rucksta View Post
Check the three large red white & black under the tank right front.
Sometimes it helps to give them a bit of a wiggle.
+1

Check the starter relay, and the main ground on the tranny. Also check the fuses.
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Old 09-05-2014, 04:46 PM   #5
Warin
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Not enough info to isolate it .. but

does the headlight flash work?
Horn?
Stop light?
Indicators/blinkers?

if those function then I'd go to the 'light relay' ...
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Old 09-11-2014, 10:56 AM   #6
meijer's trails OP
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Thanks guys. Sorry for the delayed response. I am grateful to all of you who take the time to help others.

Well, the headlight flash works fine. The headlight works. The taillight works.

The horn does not work. The brake light does not work.the turn signals do not work.

Does that helpfully narrow it at all?
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Old 09-11-2014, 03:24 PM   #7
DustyOne
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as a self-taught airhead basic mechanic,
at this point, I do not have anything in particular to consider that has not already been said

as a recently educated airhead electrical gremlin analyst,
the way I would attack this would be to first look at that electrical wiring diagram, follow all of the wires/connections to find out just what is in-common to all of those items that do not work........and then, there is the problem

and then, pull out your electrical test lamp and testing meter, roll up your sleeves, and GET-TO-IT

there is a ground connection coming out of the turn-signal-relay that seems to also affect several other of the items that you have mentioned....that might be a good place to start looking around at, and go from there.

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Old 09-12-2014, 05:45 AM   #8
Udo
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Horn, brake light, turn signals. That connector at the lower left corner of the schematic (above the turn signal switch) seems to be a common route for the three failed circuits.
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Old 09-12-2014, 11:43 AM   #9
Big Bamboo
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A friend with a '91 GS had no brake light or rear turn signals. Traced it to the turn signal cancelling switch. A shot of electronics cleaner with lube and, "voila!". That said, the tach gets it's signal from the small black wire connected to the coil. Perhaps some cleaning and tightening of that connection is in order.
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Old 09-12-2014, 08:02 PM   #10
Ixheimer
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Is the wiring harness on the bike the original? If so, check the bundle where it runs under the front wheel mud guard and up to the headlight. That area gets a lot of flex over the years each time the handlebars are turned. I recently replaced the main loom with a new one because I had so many splices & repairs to cracked wires in that area. Remove the front mudguard & you may have to cut through an outer protective sleeve to check the condition of the wiring there.

Here's what mine looked like before I replaced the whole shebang. It was getting to the point that every time I turned the bars far enough, certain electrics would cut out, even the ignition at one point. May not be the case for you, but if it's the original wiring, might not be a bad idea to consider ordering a new main loom.







Fuses are always a good thing to check first, but that's already been mentioned.

Ixheimer screwed with this post 09-12-2014 at 08:09 PM
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Old Yesterday, 05:04 PM   #11
meijer's trails OP
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Thanks for all the help guys.

The problem was indeed a fuse...but the backside of the fusebox!

There was an enormous amount of corrosion on the connectors on the BACK(which is forward on the motorcycle) of the fuse box where the wires connect to the fuses.. The fuses themselves were clean. My clymer manual indicates more modern spade fuses, but my 81 g/s has a little black plastic box, and inside are the same old ceramic fuses my older BMW uses.

There was also corrosion,I believe between the wire side spade and the fuse side spade. Those pieces are rivited together. And I believe corrosion formed between the layers.

So i remove the fusebox, I used a tiny dremel brush to clean everything. Then I used a very sharp punch to lightly "micro-stake" the rivit back onto, and smear into, the clean portion of the spade. More deoxit and new fuses.

I did also find a worn wire just aft of the steering stem left side under the tank, on the green black related wire but this was wearing on another vinyl bundle so I doubt if it was a cause. Some deoxit and careful taping in that spot.

This fixed my problem.

But "while I was in there"..... and you all know how this goes...
I decided on a dental hygiene style of scrape/clean/deoxit every connector and relay I could find

Thanks again guys
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