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View Full Version : Keep popping brakelight/horn 7.5A fuse



inlinejohn
07-24-2010, 11:04 AM
History:

I recently installed LED rear tail lights w no issues during installation and EVERYTHING worked, except blinkers....need to install relay soon.

I keep popping the 7.5A fuse that drives brake light and horn. It does NOT pop when bike isn't running, but key on. Works just fine in the garage. I've tried sitting on the bike, bouncing around, shaking, steering, etc but cannot reproduce the popped fuse. I start bike, it still works fine.

Once I take off, it pops.....arrrrggghhh! I don't get it. I've looked the bike over and over and over for loose wires, sparking, etc.....nothing????

Going to ride again today...soon and will try to see what exactly causes....relative to my ride style. It's frustrating, cuz I hate riding w/o brake light.

Your thoughts???

motodave
07-24-2010, 01:28 PM
Well a fuse is going to blow due to a short or too much power(electrical) If you dont have measuring equipment (ohm/volts meter) then I would start by unplugging the parts that are controled by this fuse and try to get the fuse to blow one by one when plugging back in these parts, ie; tail light, dash,....
Now for having to much electrical voltage I would inspect the charging system at just above idle and see if it goes above 14.8 volts( that is normal for a modern bike but yours would likely be around 13.5 volts) if it goes above 15-15.5 volts chk your reg/rec or unplug it and see if the fuse stops blowing....... now all of this can work if you are prepared to use from 1 -?? fuses for testing.
You can always call me at the store and I can help you out over the phone if needed....
:)


History:

I recently installed LED rear tail lights w no issues during installation and EVERYTHING worked, except blinkers....need to install relay soon.

I keep popping the 7.5A fuse that drives brake light and horn. It does NOT pop when bike isn't running, but key on. Works just fine in the garage. I've tried sitting on the bike, bouncing around, shaking, steering, etc but cannot reproduce the popped fuse. I start bike, it still works fine.

Once I take off, it pops.....arrrrggghhh! I don't get it. I've looked the bike over and over and over for loose wires, sparking, etc.....nothing????

Going to ride again today...soon and will try to see what exactly causes....relative to my ride style. It's frustrating, cuz I hate riding w/o brake light.

Your thoughts???

Adrian749s
07-24-2010, 05:02 PM
Does it have a resistor in line with the brake light? LED's have lower resistance than a regular bulb, so that causes amp flow to go up and could cause your fuse to blow.

Adrian

Lotus54
07-24-2010, 05:33 PM
A typical LED Taillamp has less current draw.
But there are resistors in the assym to keep the current low in the individual LEDs so they don't get cooked right away.

If the fuse is blowing, something is drawing too much current.
Does sound like 'short' to ground. If the voltage goes up, current goes down (all else equal, Ohm's law).

Those are sometimes pretty hard to find.
I'd proabaly take off as much bodywork as possible and look for wing looms tha are chaffed.
I forget what else is on tha circuit, any chance the horn is on it and shot?

Mark

inlinejohn
07-24-2010, 09:10 PM
thoroughly inspected bike this morning, new fuse, brake light/horn working. Could not reproduce problem all day with lots of miles today, so not sure why it's ok now??? The gen light does dim now and then, but not sure what that means?? Maybe it magically fixed itself.