bret
'81 Special
My main fuse shorted so I bought some new ones and replaced it. Now when I turn the bike on the neutral light is very dim and the bike eventually shuts off. Any ideas on why the main fuse might be shortening?
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Main fuse is shorting
- Thread starter bret
- Start date
-
- Tags
- electrical issue
Well, first a little vocabulary lesson:
1. A "short" is either a direct path from power to ground (hot lead touching the chassis for instance) or an unintended path between two wires (insulation rubbed off).
2. A fuse doesn't "short" it "opens" or in more common terms "blows". It does this because a "short" (see #1 above) has caused excessive current draw and the fuse blows to keep the wiring harness from melting down and/or starting a fire.
Now that we have our terms clear, your fuse is most likely blowing from one of three reasons:
1. You have a main power lead shorted or partially shorted to ground, usually due to worn insulation allowing the wire to touch the frame or some other metal object.
The solution here is to visually inspect the entire wiring harness looking for rub points, worn or cracked insulation, partially undone connectors, etc.
2. A component (switch, ignition module, light socket, reserve lighting unit, or any one of several others) has failed or is failing in such a way as to create an overcurrent situation.
The solution here is to unplug each component one at a time and see which one causes the problem to go away.
3. Someone has replaced the fuse with a fuse of too low a value. IIRC, the main fuse should be a 20 amp fuse. If it has been replaced with say a 10 amp, then normal loads may cause it to blow.
This doesn't cover ALL the possibilities, but it does address the most common causes of blown fuses.
Check it out and let us know what you find.
Edited to add: Your dim neutral light and eventual stalling indicates an overload pulling the battery voltage down. The ignition on XS's requires full battery voltage to work properly. All of the investigative steps above apply.
1. A "short" is either a direct path from power to ground (hot lead touching the chassis for instance) or an unintended path between two wires (insulation rubbed off).
2. A fuse doesn't "short" it "opens" or in more common terms "blows". It does this because a "short" (see #1 above) has caused excessive current draw and the fuse blows to keep the wiring harness from melting down and/or starting a fire.
Now that we have our terms clear, your fuse is most likely blowing from one of three reasons:
1. You have a main power lead shorted or partially shorted to ground, usually due to worn insulation allowing the wire to touch the frame or some other metal object.
The solution here is to visually inspect the entire wiring harness looking for rub points, worn or cracked insulation, partially undone connectors, etc.
2. A component (switch, ignition module, light socket, reserve lighting unit, or any one of several others) has failed or is failing in such a way as to create an overcurrent situation.
The solution here is to unplug each component one at a time and see which one causes the problem to go away.
3. Someone has replaced the fuse with a fuse of too low a value. IIRC, the main fuse should be a 20 amp fuse. If it has been replaced with say a 10 amp, then normal loads may cause it to blow.
This doesn't cover ALL the possibilities, but it does address the most common causes of blown fuses.
Check it out and let us know what you find.
Edited to add: Your dim neutral light and eventual stalling indicates an overload pulling the battery voltage down. The ignition on XS's requires full battery voltage to work properly. All of the investigative steps above apply.
Last edited:
jd750ace
Front Toward Enemy
You could pull all the other fuses, and check the output side of them for continuity with ground. If one (or more, hope not) shows continuity with ground, that is the problem circuit, and should shorten the hunt. Don't "fuse check" it, use a meter. the more you apply current to a shorted circuit, the more it degrades the wiring, and you might burn your ride to the ground.
bret
'81 Special
Turns out my broken signal wire was hanging out loose. Must have been the weather that caused a short.
